The ESATTO 3.5″ LP – M98 → M72 F Adapter (PrimaLuceLab, SKU: PL3600385) allows you to connect accessories with an M72 × 1 male thread (e.g. a flattener or a Takahashi, William Optics, TEC focal reducer) to the ESATTO 3.5″ LP low-profile focuser. The adapter screws directly into the M98 collar of the focuser, maintaining a minimal optical length so that the valuable back-focus reserve remains almost intact.

The most important features of the adapter

• adapter from internal thread M98 × 1 (ESATTO side) to internal thread M72 × 1
• optical length of only 4 mm – ideal for a strict back-focus budget
• 6061-T6 aluminum body, hard anodized in red PrimaLuceLab
• precisely turned threads with a tolerance of ±0.02 mm – reliable and axial assembly of heavy correctors
• engraved raster for easy grip and tightening when wearing gloves

Set components

• M98 → M72 F adapter for ESATTO 3.5″ LP
• 3 × M3 locking screw (prevents self-loosening during rotation)

Technical parameters

• thread on the extractor side: M98 × 1 (external)
• accessory side thread: M72 × 1 (internal)
• optical length: 4 mm
• Outer diameter: 104 mm
• material: 6061-T6 aluminum, hard anodized
• weight: 95 g
• manufacturer: PrimaLuceLab – Italy

With this adapter you can seamlessly integrate correctors and reducers with M72 thread into the ESATTO 3.5″ LP focuser, creating a fully rigid and precise optical path even for full-frame cameras. The minimal thickness of the ring guarantees that there will be enough back-focus for a circular filter, ARCO 3″ rotator or off-axis guider.