I needed some more pills for my B158, and it just so happens that UF-1508 pills fit and work. Good thing I have about 10 of those.
Pics for reference.
B158
UF-1508
Shelf looks deeper on the 1508. Does it tighten the beam?
The shelf is approximately the same as led in the one I used was perfectly focused. The 1508 pills have higher walls that extend up from the shelf, and slightly more room in driver area. I didn’t think it would be focused, but the 1508 was.
Will a regular size MPCB fit on the shelf of 1508? Brynites are that odd size that take extra work.
Brian
1508 takes a 17mm driver and 16mm led pcb.
That is how I lost my B158 pill with BLF-A6 driver and dedomed XP-G2 S4 2B led.
One night modding with Nicolaas (another BLF member from Amsterdam) we took a chance fitting my B158 pill to his 1508 and it was an exact fit and it made over 600 kcd. There was no way of not giving that pill to him after that. 
Any source for empty pills?
They are discontinued at Gearbest.