I have a TrakPower 4800 LiPo saddle pack for sale.
This is the tall type (see TrakPower website for specs/dimensions) - Not BRCA legal but great for club racing, etc...
Comes complete with 4 long battery posts & screws to enable fitment into B44, D4, BMax, etc.
Very little use (would estimate approx 10 uses) as used in a spare car. Heatshrink has been removed (fitment reasons) - Otherwise great
£25 posted (UK)