Polaroid 405 and 550 holders will accept the appropriate Fuji products. The holders (and the Fuji branded ones as well) are a fat 1 inch thick. Meaning slightly more than 1 inch thick. These holders work best with a Graflok back. Remove the ground glass and attach the holder for a photograph. The holders may, or may not, fit by sliding the holder under the ground glass. The DO NOT slide under my Zone VI ground glass. The springs are too short and the fit is just too tight.
I thought we expalined Graflok backs & Polaroid holders earlier?
Polaroid ceased production 2+ years ago.