This cover fits perfectly on a Takahashi FS-152 mounted on a NJP mount. Ive used this same cover on a FSQ-106 and GM-8 mount as well. Its stood up to some fierce Texas sun, wind and thunderstorms without any damage. I plan to buy a second one for another scope. I do secure my cover with a long velcro strap as an extra measure and have never had issue with the cover coming off or rain blowing up into the cover.