The M81 → T2 (M42 × 0.75) adapter with stop ring for ESATTO 3" / ARCO 3" (PrimaLuceLab, SKU: PL3600282 ) allows you to connect cameras and accessories in the popular T2 standard to the ESATTO 3" focuser or ARCO 3" rotator (M81 × 1 thread). The integrated stop ring allows for precise adjustment of the adapter's screw-in depth and locking in the selected position, which makes it easier to maintain the correct back-focus and orientation of the connected device.

Key Features

• Thread conversion: input M81 × 1 (ESATTO 3" / ARCO 3") → output M42 × 0.75 (female, T2)
• stop ring – precise position adjustment, secure adapter lock
• optical length of only 7 mm – minimal impact on the back-focus budget
• internal grooving and black anodizing – reduced reflections, better contrast
• CNC milled body made of 6061-T6 aluminum – lightness, stiffness, corrosion resistance

Set components

• M81 → T2 adapter with stop ring
• Allen screw locking the ring

Technical parameters

• input thread: M81 × 1 (female)
• output thread: M42 × 0.75 (female; T2 standard)
• optical length: 7 mm
• Inner diameter: 42 mm
• material: aluminum 6061-T6, black anodized
• compatibility: ESATTO 3", ARCO 3 rotator, T2 accessories
• EAN: 8059020773236
• manufacturer: PrimaLuceLab – Italy

PL3600282 is a practical accessory when you want to connect the wide ESATTO 3" focuser or the ARCO 3" rotator to a camera or other device in the T2 standard, maintaining full back-focus adjustment and mechanical stability of the entire optical system.