Filter Retaining Masks for ZWO EFW Mini (SKU: ZWO EFW-5-MASKS) are a set of 10 masks designed to secure round 31 mm unmounted filters in the earlier-generation ZWO EFW Mini five-position filter wheel. The masks hold the filters around their edges, leaving a clear aperture of 27.3 mm.

Each mask has three mounting holes and attaches to the filter wheel carousel using the included M2 × 4 screws. The set allows worn or missing retaining components to be replaced and provides spare masks for future use.

Compatibility: the EFW-5-MASKS version is designed for the earlier ZWO EFW Mini filter wheel. For the EFW-5x1.25-25 model introduced in 2025, the manufacturer specifies the separate EFW-8-MASKS set.

Key features

• secures round 31 mm unmounted filters
• designed for the earlier-generation ZWO EFW Mini five-position filter wheel
• 27.3 mm clear aperture
• three mounting points on each mask
• set of 10 masks with mounting screws

Included items

• ZWO EFW Mini filter retaining masks – 10 pieces
• M2 × 4 Phillips flat-head screws – 1 set

Technical specifications

• manufacturer: ZWO
• model designation: EFW-5-MASKS
• compatible filter wheel: earlier-generation ZWO EFW Mini, 5 positions
• supported filters: round, 31 mm, unmounted
• mask clear aperture: 27.3 mm
• number of mounting holes per mask: 3
• mounting hole diameter: 2.2 mm
• mounting screws: M2 × 4
• mask colour: black
• number of masks included: 10