KOLTEC USA's pad for Hook & Loop discs are typically used in finishing and polishing applications with hook & loop sanding discs. Pads with water feed holes are commonly used in the polishing of marble, granite, and other ceramic material in a wet mode. These back-up pads can be used in both wet and dry applications.
Pads with a foam inter-layer and a water feed hole can be used wet or dry.
Pads without a foam layer offer a firmer action. These are only recommended for Dry applications.
The 6" x 5/8"-11 pad with no foam layer, also does NOT have a water hole.