This is a new (but no box) Meade dust cap for 5" newtonian reflectors. (ones with a 5" diameter mirror) This comes off of the Meade DS-2130AT telescope. It fits at the top end of the tube and keeps dust out. Very important as you don't want to clean the mirrors. The coatings rub off and get scratched very very easily. Sometimes if you just look at them wrong. Anyway, if you have a Meade Newtonian with a 5" mirror this should fit if it was made after 1990. This is original equipment and will help keep the scope nice. At this price you can't go wrong!