CESFONJER 12 Pack Plastic Push to Connect Fittings Tube Connect 1/4 inch Straight od Push Fit Fittings Tube Fittings Push Lock (6mm: Y+T+I Type Combo)

Yes it connects 6mm pipe. Thats the only good thing I can say.I used it to connect 6mm airline for a CO2 system for an aquascape aquarium that runs at 0.20 bar. These didnt hold any pressure what so ever and ended up in the bin.

Connecting air lines on my van, fitted pipes perfectly, very good fit