All Material : Aluminum Alloy Length: 6.8cm Diameter: 4.4cm Thread Thread : M42x0.75 This adapter is not limited to shooting with the eyepiece. It is a must have for magnification. Very sturdy construction for peace of mind Compatible with 31.7mm M42*0.75 astronomical telescope eyepieces Package includes: 1 X Magnifying Adapter 1 X 1.25" T-Mount