they accept coupling plugs (nipple or male ends) to connect tools to air

NK SPOUT 166_16_950

Bradley Mills Partition Continuous Stainless Steel Urinal Screen Kit

Number of Lights: 3

The ASI 04523 Manual Roll Paper Towel Dispenser accommodates one standard paper towel roll that measures 8 inches diameter and 8 or 9 inches in length

3M 50 ft Absorbent Roll, Fluids Absorbed: Universal, Heavy, 10.5 gal, 1 EA - M-FL550DD/M-F2001 Nominal Size-24" X 1.25" they accept coupling plugs (nippleItem Spill Control: Absorbent Roll; Spill Control Fluids Absorbed: Universal; Absorbency Weight: Heavy; Volume Absorbed per Pkg.: 10. 5 gal; Length: 50 ft; Width: 5 in; Material: Polyester, Polypropylene, Synthetic Fibers; Layers of Construction: 2; UV Resistant: No; Recycled Content (%): 25%; Perforated: Yes; Color: Gray; Item: Absorbent Roll; Static Dissipative: No