Extension ring with a 2-inch outer diameter. Hyperion Finetuning Ring 28 mm for Baader Hyperion eyepieces and M48 extension. The extension ring features M48 x 0.75 filter threads on both sides and has a length of 28 mm. The adapter is made of aluminum and is black anodized. The magnification of the Hyperion eyepieces increases by approximately 40%. Screw the extension ring between the lower element of the Hyperions and the eyepiece body, which reduces the focal length of the eyepiece by about 40%. The magnification increases by the same amount. It can be used as an M48 extension ring. Especially in astrophotography, it is often necessary to establish a precisely defined distance from the corrector to the camera sensor; this ring helps with that. Thread: M48 x 0.75 on both sides (male/female). Length: 28 mm. Length of M48 internal thread: 3 mm.