The Telescoop; RollerShutter parts patented by H.Hünker
Amazon.com: Learning Resources Science Kits for Kids Age 3+, STEM Projects of Weathervane Periscope Telescope Roller, 4 Sets Scientific and Physics Educational Teaching Aids for Primary School Students : Toys & Games
12 inch Black Rubber Keel Roller for Boat Trailer -23726
After 135 Years, UVA's McCormick Observatory Gets Its First New Dome Rollers
Ashland Conveyor Telescope Conveyor, 50 ft. L, 39-1/4 In W T5A53214TLEFG | Zoro