Based on this product's specifications, here are some alternatives and similar models
Compression Sleeve TECE 16 mm 704016 — pipe connection fitting for 16mm tubes
Summary description:
TECE compression sleeve for 16 mm tubing (model 704016) is a metal fitting designed for secure mechanical connection of 16 mm plastic or multilayer pipes. The sleeve enables reliable, leak-resistant joints in plumbing and heating installations, suitable for potable water and central heating systems. Use for straight connections, repairs and replacements in residential and commercial piping.