Product Description: All metal construction and anodizing aluminum process, durable for long time useHigh quality anodized aluminum adapterM42x1mm male thread to M42x0.75mm female thread adapter.Converts an M42x1mm female thread to a M42x0.75mm female thread. OR Converts an M42x0.75mm male thread to a M42x1mm male thread. External Threads: : M42x1mm MaleExternal Thread Depth: 3mm/ 0.12inInternal Threads: M42x0.75mm FemaleInternal Thread Depth: 4mm/ 0.16inFlange distance: 5mm/ 0.19inTotal length: 8mm/ 0.31inInner diameter: 39mm/ 1.53inThe inner side of M42x1mm is fully irregular extinction threadsMaterial: Metalcolour: Black Package Contents: 1 x telescope accessories adapter ring Only the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.