The BA130 Bafang chainring adapter from California Ebike is a great upgrade, allowing you to mount chainrings other than the standard that is supplied with each kit.
Material: CNC machined, 6061 Aluminium, Black Anodized.
Suitable for chainrings 38t to 55t.
Also included are 5 x (M5 x 16 stainless steel screws).
Compatible with the BBS01B and BBS02B only, not the BBSHD.