text: BARSKA Model AY11240 and Model AY11238 are designed for 
  biological studies such as specimen examination. They can also 
  be used for examining bacteria and for general clinical and medical 
  studies. Simple design and use is especially useful for school 
  classroom instruction. 
  
  **MAINTENANCE**
  
  Proper care and storage of this instrument is essential. Please read 
  the following guidelines: 
  1. Keep the instrument in a dry and moisture-free location. 
  2. Do not expose to acid, alkali fumes or moisture. 
  3. Keep optical parts clean and free of dust. To clean optical parts 
   gently wipe with lens cleaning tissue and a mixture of alcohol 
   and diethyl ether. Depending on weather conditions, the 
   following are the recommended mixture ratios: 
   Wet weather: 1:2 
   Dry Weather: 1:1 
  4. After use, cover the instrument with the plastic dust cover. 
  5. If instrument is to be stored for an extended period of time, 
   remove the eyepiece and oculars and store in a moisture-proof 
   container. 
  
  **CONSTRUCTION**
  
  BARSKA Model AY11240 is a fixed tube type. For comfortable 
  observation, the arm can be easily tilted at any angle from 90o 
  vertical to 45o level. It is also equipped with a coarse adjustment 
  and fine adjustment as well as a space limiter to protect the 
  objective from contacting and damaging the specimen. BARSKA 
  Model AY11238 features a monocular tube that is slanted at a 45o 
  angle. The head rotates 360o. The Eyepiece Set Screw prevents 
  the eyepiece from falling out of the tube. 