Everything you need to upgrade your Brompton to 5, 6 or 7 speeds. The whole kit should work with any Brompton but the tensioner is designed for P Line or T Line.
I can confirm it works great on T. Super lightweight Silverock 24/20 wheels. Really nice with good quality bearings and freewheel. RUHM 7 speed derailleur and tensioner. SRAM shifter (plus cable and mounting bracket, not shown). 11-28 speed cassette plus a 32T spare if you want to give that a go. Depending on what bars you have, you may require a longer gear cable housing than the one that comes with the bike. Additionally if you use the stock brakes and you have an M bar, you may need something to help mount the shifter. I have a design I've 3D printed for my X11 that could work for you. In terms of condition the wheels are excellent with only light wear to the rims and max 200km use. Could do with a small alignment tweak easy to do on the bike. The derailleur is also great.The tensioner was scraped on a kerb but works perfectly. I'm including this at a big discount. If you're only going with 6 speed you can use the stock tensioner with a small mod anyway.
It's a really excellent set bought to allow me to tour the countryside but in the end it's looking like I'm primarily only using my T in the city so not needed any more.