Kaiser Negative Mask - 5 x 5cm

Finally a mask that actually holds the slide flat in my K4583 carrier, and the 5x5cm dimensions match my mounts perfectly. The fit is snug enough that nothing shifts between exposures, which was my main gripe with cheaper alternatives.

Using this with my K4583 carrier and it clicks in perfectly smooth, no more fiddling with loose slides. The 5x5cm frame holds the slide flat and centered without any wobble.

I ditched the cardboard shims I'd been using—this mask's precision fit in my K4583 carrier means my slides are finally square in the enlarger. The 5x5 cm outer dimensions match my mounted 35 mm frames exactly.