· The Paterson MOD54 3 Spiral Tank Accessory is a 4 x 5" sheet film holder to be used together with a Paterson Super System 4 PTP116 three-reel developing tank (not included). · The notch system, similar to 4 x 5" film itself will allow easy loading insuring that the films emulsion side faces inward for greater protection against scratching. · The holder handles up to six sheets of 4 x 5" large format sheet film, allowing for standard inversion-type agitation methods during development.