L / LL / KL Finned Tube

Wrap-on aluminium fins with an L-shaped, overlapping-L or knurled-L foot — the most economical finned tube for clean air and moderate temperatures, available from 9 mm to 219 mm base tube.

Three foot designs, one family

Type	Fin foot	Coverage	Typical use	Max temperature
L type	Single L foot, fin wound under tension	Part of the base tube remains bare	Clean air, moderate duty, HVAC and dryers	≈ 250 °C
LL type	Overlapping L foot, each fin covers the foot of the previous one	Full base-tube coverage	Corrosive or dusty air where the base tube must be protected	≈ 250 °C
KL type	Knurled L foot, knurling increases grip	Full coverage with higher contact pressure	Higher vibration, higher temperature, longer tubes	≈ 300 °C

Product Gallery

Typical specification

Parameter	Range
Base tube OD	9 mm – 219 mm
Base tube material	Carbon steel, stainless steel, copper, copper-nickel, alloy steel
Fin material	Aluminium 1060 / 1100 / 3003, copper
Fin height	6 mm – 25 mm
Fin pitch	2.3 mm – 5.0 mm
Fin thickness	0.25 mm – 0.5 mm

When to choose L, LL or KL

1. Use L type when the air is clean, the duty is moderate and cost matters most.
2. Use LL type when the base tube needs protection from corrosion — the overlapping foot shields the tube surface.
3. Use KL type when vibration, longer spans or higher temperatures call for a stronger grip on the fin foot.

All three types are produced on the same winding lines, so mixed batches and short runs are not a problem.