FIELD OF THE INVENTION 
   The invention relates generally to attachment devices having a fluid-containing cavity. 
   BACKGROUND OF THE INVENTION 
   Attachment devices such as snap hooks and carabiners have long been in use for providing a means for attaching articles to each other. Such devices have numerous applications, such as for example enabling multiple articles to be secured to a backpack, purse, handbag, key chain or the like. As such, these devices are fairly ubiquitous. An example of an attachment device is a carabiner such as is disclosed in U.S. Pat. No. 5,005,266. 
   Fluid-filled ornamental articles are known in the art. For example, U.S. Pat. No. 4,148,199 relates to a pierced earring with liquid visible therein. U.S. Pat. No. 4,093,973 relates to a liquid filled ornamental article of jewelry containing an illumination source. U.S. Pat. No. 5,006,375 relates to an ornamental article having a transparent housing shaped into a decorative configuration having a liquid therein and a subatmospheric pressure area between the liquid and housing. However, none of the prior art liquid filled ornamental articles have the utility of providing a means for attaching articles to each other and providing an indicia bearing means on a ubiquitous useful article. 
   SUMMARY OF THE INVENTION 
   The invention provides an attachment device comprising at least one fluid filled cavity formed therein. The attachment device is preferably in the form of a carabiner in which at least a portion of the carabiner body is formed of a transparent material such that the fluid filled cavity is visible. In a preferred embodiment an indicia bearing means is visibly disposed within said cavity. 
   OBJECTS OF THE INVENTION 
   It is an object of the present invention to provide a fluid filled attachment device that is aesthetically pleasing. 
   It is a further object of the present invention to provide a novel attachment device that provides an interior fluid filled cavity capable of containing an indicia-bearing medium. 
   It is still a further object of the present invention to provide in a novel attachment device a free-floating indicia-bearing medium in said fluid filled cavity. 
   It is yet a further object of the present invention to provide in a novel attachment device a fixed indicia-bearing medium in said fluid filled cavity. 
   It is still a further object of the present invention to provide a novel attachment device in the form of a carabiner that provides an interior fluid filled cavity capable of containing an indicia-bearing medium. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view of a preferred embodiment of the present invention; 
       FIG. 2  is a perspective view of a preferred embodiment of the invention of  FIG. 1 ; 
       FIG. 3A  is a cross sectional view of the invention of  FIG. 2  taken along the line A-A′; 
       FIG. 3B  is a cross sectional view of another embodiment of the invention of  FIG. 2  taken along the line A-A′; 
       FIG. 4  is a perspective view of a further preferred embodiment of the present invention; 
       FIG. 5  is a cross sectional view of the invention of  FIG. 4  taken along the line B-B′; and 
       FIG. 6  is a perspective view of a further preferred embodiment of the present invention. 
       FIG. 7  is a perspective view of a further preferred embodiment of the present invention. 
       FIG. 8  is a front perspective view of a further preferred embodiment of the present invention. 
   


   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Now referring to  FIGS. 1-3 , a preferred embodiment of the device  2  comprises essentially a body member  10 , at least one openable gate member  20 , at least one cavity  30  formed in the device  2  and a fluid  35  contained in said cavity  30 . Device  2  optionally further includes an indicia-bearing device  40  contained in said cavity  30 . 
   Body member  10  comprises an elongated member comprising a first end and a second end and is fabricated of any material suitable for attachment devices such as but not limited to bare or coated metal, wood, rubber or plastic or combinations thereof. Gate member  20  comprises an elongated member pivotally attached at one end to one end of said body member  10 . The other end of gate member  20  contacts the other end of said body member  10  when said gate  20  is in a closed position. Now referring to  FIG. 2 , in a preferred embodiment gate member  20  is inwardly openable. Gate member  20  is fabricated of any suitable material as recited above for body member  10 . In a preferred embodiment body  10  is curvilinear. In a most preferred embodiment body member  10  is formed in the shape of a carabiner. 
   Cavity  30  is formed in either or both of body member  10  and gate member  20 . Cavity  30  may be formed of a depression or hollow in the material of body member  10  or gate member  20 , for example where the material is formed of a nontransparent material such as metal, wood, rubber or opaque plastic and sealed with a transparent material such as but not limited to readily available plastics or acrylics, polycarbonates, polyimides, methacrylates, polystyrenes or the like such that the interior of the cavity  30  is visible. Now referring to  FIGS. 2 and 3 , alternatively, where the material of the portion of the device  2  wherein the cavity  30  is formed is a transparent material the cavity  30  can be a chamber formed therein by thermoforming, blow molding, boring or the like. Now referring to  FIGS. 4 and 5 , in yet another embodiment cavity  30  is formed between a portion of body member  10  and a transparent shell member  12 . 
   Fluid  35  is any suitable substance that is nonreactive when employed in conjunction with the material of cavity  30 . Suitable fluids  35  include colored or uncolored liquids such as but not limited to water, oil or gel or mixtures thereof; or, as seen in  FIG. 2 , small particulate matter  37  such as but not limited to colored or uncolored powders, grains or the like or mixtures thereof; and/or as also seen in  FIG. 2  at  35  and  37  mixtures of liquids and solid particles. In a preferred embodiment fluid  35  is transparent. As is also seen in  FIG. 2 , those skilled in the art will recognize materials such as reflective or refractive material including but not limited to glitter and/or other insoluble material  37  may be included in fluid  35  for aesthetic purposes. It will also be recognized fluid  35  may contain a colorant. It is to be understood herein that each and every other of the embodiments of the other figures herein may also have the above particulate matter, glitter. etc.  37  within fluid  35 . 
   Indicia bearing device  40  is contained in cavity  30  and may be fixedly anchored within said cavity  30  (as seen in  FIG. 3B ) or may be unanchored so as to be free-floating or free-moving within said cavity  30  (as seen in  FIG. 3A ). Accordingly indicia bearing device  40  may be fabricated of any suitable material that is nonreactive with fluid  35 . Suitable materials are any materials capable of receiving indicia such as ink, engraving, paint, or the like and include but are not limited to metal, wood, laminate, plastic, cork, rubber and the like. Indicia bearing device  40  may have any configuration as long as such configuration can be received and contained in said cavity  30 . Now referring to  FIGS. 2 and 3  in a preferred embodiment indicia bearing device  40  is elongated and has a three dimensional cross section, providing more than one indicia bearing surface  42 . As seen in  FIG. 3 , in one embodiment indicia bearing device  40  comprises three indicia bearing surfaces  42  and each surface  42  may for example bear different indicia. 
   In a preferred embodiment device  2  comprises a curvilinear body  10 , body  10  comprises metal having at least one cavity  30  formed therein, said cavity  30  sealed by a transparent plastic material, said cavity  30  containing a fluid  35  comprising water and further containing indicia bearing device  40 , wherein said indicia bearing device  40  is elongated and is free floating in fluid  35 . 
   Now referring to  FIG. 6  in a most preferred embodiment device  2  comprises a cavity  30  formed in gate  20  and body  10  is in the shape of a carabiner. 
   Now referring to  FIG. 7 , in an alternate preferred embodiment body  10  is in the form of a circle. 
   Now referring to  FIG. 8 , in a further preferred embodiment of the present invention, cavity  30  comprises a significant portion of the device  2 . 
   As illustrated in  FIGS. 7 and 8 , device  2  is not limited to the form of a carabiner but may take any suitable shape or form. 
   While the preferred embodiments have been described and illustrated it will be understood that changes in details and obvious undisclosed variations might be made without departing from the spirit and principle of the invention and therefore the scope of the invention is not to be construed as limited to the preferred embodiment.
An attachment device is provided comprising at least one fluid filled cavity formed therein. The attachment device is preferably in the form of a carabiner in which at least a portion of the carabiner body is formed of a transparent material such that the fluid filled cavity is visible. In a preferred embodiment an indicia bearing means is visibly disposed within said cavity.