Astromania M54X0.75 Male to M48X0.75 Female Thread Telescope Adapter. One side is M54X0.75 Male thread, the other side is M48X0.75 Female thread. Converts an M54 female thread to a M48 female thread. All metal construction and anodizing aluminium process, durable for long time use. This is a very high quality anodized aluminum adapter.