AmScope DK-DRY100 Dry Darkfield Condenser For Compound Microscopes
This is a high quality dry darkfield condenser for industry standard compound microscopes. It comes with mounting size 37mm in diameter.  Features & Specifications:  Darkfield Condenser: Dry Mounting Size: 37mm, industray standard NA: 0.7-0.8 Shipping Weight: 1 lb