The M81 → M48 (M48 × 0.75) adapter with stop ring for ESATTO 3" / ARCO 3" (PrimaLuceLab, SKU: PL3600277 ) allows you to connect cameras, filters or other accessories with an M48 × 0.75 external thread to the ESATTO 3" focuser or ARCO 3" rotator (M81 × 1 thread). The integrated stop ring allows you to precisely set the adapter's screw-in depth and lock it in the selected position, which facilitates back-focus control and the orientation of the attached accessory.

Key Features

• thread conversion: input M81 × 1 (ESATTO 3" / ARCO 3") → output M48 × 0.75 (female)
• stop ring – precise position adjustment and secure adapter lock
• optical thickness of only 7 mm – minimal impact on the back-focus budget
• internal grooving and black anodizing – effective reflection reduction, better contrast
• CNC milled body made of 6061-T6 aluminum – light, stiff and corrosion resistant

Set components

• M81 → M48 adapter with stop ring
• Allen screw locking the ring

Technical parameters

• input thread: M81 × 1 (female)
• output thread: M48 × 0.75 (female)
• optical length: 7 mm
• Inner diameter: 48 mm
• material: aluminum 6061-T6, black anodized
• compatibility: ESATTO 3" lift, ARCO 3" rotator, accessories with M48 × 0.75 thread
• EAN: 8059020773243
• manufacturer: PrimaLuceLab – Italy

PL3600277 is a practical solution when you want to connect a wide ESATTO 3" focuser or ARCO 3" rotator with a camera, filter or other accessory in the M48 standard, while maintaining full back-focus adjustment and the stability of a mechanical connection.