I bought close to $50 in these for my barn.  Glad i bought so many because 75% of them break while  you are opening them.  They are so cheaply made the yellow part breaks the tape at different lengths, sometimes it left me with 2 inches of tape, sometimes 1 inch, sometimes 10 inches of tape to catch the flys.  Save your money, as I thought this was a good deal but ended up being a POS.