Model Compatibility: Fits drum cleaning applications for models 163, 165, 166, 167, 203, 203L, 205, 206, 207, 255, 256, 257, 280, 282, 283, 181, 237, 307, 3508A, 357, 457, and 507. Quantity Included: Contains exactly five drum cleaning units per package as specified in the title. Functionality Purpose: Designed to serve as a functional for drum cleaning tasks on the listed model numbers. Specification Match: Matches the dimensional and operational requirements necessary for drum cleaning on all models explicitly named in the title. Installation Scope: Intended for direct use in drum cleaning systems of the 22 listed model numbers without modification.