Classification by standard nominal diameter (DN)
Small-diameter series: DN15, DN20, DN32, DN40, DN50; primarily used for residential service lines and small branch pipe repairs (e.g., the common DN50×140mm straight-pipe repair clamp).
Medium-diameter series: DN65, DN80, DN100, DN150, DN200; standard specifications for municipal water supply and fire-fighting pipelines, compatible with common materials such as PE, PVC, and ductile iron.
Large-diameter series: DN250 to DN1000 (with some manufacturers offering customization up to DN4000); used for large-scale water transmission mains and industrial pipeline repairs.
Outer diameter (OD) series: Some models are designated by Φ (ranging from Φ20mm to Φ630mm) to correspond with the actual outer diameters of PE or PVC pipes.