This slim, low-profile design allows the Bubblevel to be mounted on most scopes without removing the scope from the rifle. It is easily visible without losing the sight picture. Mounts quickly and easily to the riflescope tube. Made in the USA. Features: Slim, low-profile design Will mount on most scopes without requiring you to remove the scope from your gun Easily visible without losing the sight picture Specifications: Outside Diameter (inches) 2.2 - 2.4 inches Outside Diameter (mm) 55 - 61 mmWeight 0.5 oz