[black] three-layer stainless steel pipe

[white] three-layer stainless steel pipe

[black] four-layer stainless steel tube

[white] four-layer stainless steel tube

[black] five-layer stainless steel tube

[white] five-layer stainless steel tube

[black] three-layer pp pipe

[white] three-layer pp pipe

[black] four-layer pp pipe

[white] four-layer pp pipe

[black] five-layer pp pipe

[white] five-layer pp pipe