People there were very helpful in finding the right pad holder I needed. This one was different than the ones on our other machines.
Caster Swivel.  4.0X2.0. Fits Nilfisk Advance Adhancer, Warrior, Aquamatic Selectric, Convertamatic (260B, 260BHD, 32B, 32BD, 38BD, 320BHD, 380BHD), Hydro-Retriever (260BHD, 320BHD, 380BHD), AquaMAX AX 650.
Fits Nilfisk Advance 56365555
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