Croker manufactures fire department connections (Siamese and FDC inlets), valves, and hose accessories for fire-protection systems. The brand is widely specified on standpipe and sprinkler risers in commercial buildings.

Cuno Filtration Systems, now part of 3M, produces commercial water-filtration cartridges and housings used in foodservice, healthcare, and industrial water treatment. Its filters are common in coffee and ice machines, dental units, and pharmaceutical processes.

Danfoss is a global manufacturer of HVAC and refrigeration components including thermostatic expansion valves, scroll compressors, frequency drives, and hydronic balancing valves. The Danish company is a key supplier to OEMs and mechanical contractors.

Dawn Kitchen & Bath supplies stainless steel kitchen sinks, bar sinks, and accessories ranging from drop-in to undermount and apron-front configurations. Its product range covers residential and light-commercial applications.

Delta Faucet Company is one of North America's largest faucet manufacturers, producing kitchen, bath, and shower fixtures for residential and commercial use. Its Touch2O, H2Okinetic, and DIAMOND Seal technologies are signature features of the brand.

As the world's largest manufacturer of HVAC/R equipment pads, DiversiTech is the go-to supplier of all size ranges and substrate types, from concrete to composites. Struts, brackets, clamps and blocks round out DiversiTech's equipment mounting offering.

Dixon Valve & Coupling manufactures industrial hose, fittings, and quick connectors for fluid and pneumatic transfer in fire, food, oilfield, and process applications. Its cam-and-groove and KC compression products are stocked across distribution channels.

Dundas Jafine produces flexible ducts, dryer vent kits, range-hood ducting, and indoor-air-quality accessories. Its products are stocked at HVAC wholesalers, big-box retailers, and through homebuilders.

Dura Plastic Products manufactures Schedule 40 and 80 PVC fittings for irrigation, pool, spa, and water-distribution systems. The made-in-California brand is a fixture on irrigation and plumbing trucks across the western U.S.

DuraVent makes factory-built venting and chimney systems for gas, oil, wood, and pellet appliances, including its DirectVent Pro, PelletVent Pro, and DuraTech lines. The brand is widely specified for hearth, water heater, and high-efficiency boiler installations.