I was changing shells too vigorously and my white metal locking tab with the hook on it broke.
By the way, it defies the laws of physics, but if you slide fast enough you'll somehow bypass the lock and take the tube off, I solved this by jamming a bit of vinyl eraser under the other side of the tab so it can't be unlocked.
Anyway the hook broke off so I made a replacement out of steel, we have a rotary table and I could have made a program to make several, but I figured it would be close enough if I just machined it in several setups and I only made one
It's profiled out with a roughing endmill (thus the surface finish), and then cleaned in M.E.K.(thus the sheen)