The M110 → M98 adapter with stop ring for ESATTO 4" (PrimaLuceLab, SKU: PL3600322 ) enables the connection of M98 × 1 threaded accessories to the ESATTO 4" focuser, whose front thread has a diameter of M110 × 1. The integrated stop ring allows you to precisely set the adapter's screw-in depth and lock it in the selected position, which makes it easier to maintain the correct back-focus and orientation of the attached accessory.

Key Features

• Thread conversion: input M110 × 1 (ESATTO 4") → output M98 × 1
• stop ring – precise position adjustment and secure adapter lock
• full 98mm internal diameter – no vignetting for full frame sensors
• CNC milled 6061-T6 aluminum, hard anodized – lightweight and rigid construction
• blackened, grooved interior - effective reduction of reflections, better contrast

Set components

• M110 → M98 adapter with stop ring
• Allen screw locking the ring

Technical parameters

• input thread: M110 × 1 (female)
• output thread: M98 × 1 (male)
• optical length: 7 mm
• Inner diameter: 98 mm
• material: aluminum 6061-T6, black anodized
• Compatibility: ESATTO 4" extractor and accessories with M98 × 1 thread
• EAN: 8059020773786
• manufacturer: PrimaLuceLab – Italy

PL3600322 is a practical solution when you need to precisely adjust the back-focus and connect a corrector, reducer or other accessory with M98 thread to the wide ESATTO 4" extension tube, while maintaining the full aperture and rigidity of the entire optical system.