Looking for help with 2 oddball Ozito batteries. My son recently bought a Ozito cordless chainsaw kit from Bunnings model OCS 018. The kit has a single 2 A/hr battery so he soon was looking for an additional battery only to find the PCX battery they sold him did not fit.  The kit battery is marked "For OCS 018" but seems to be an oddie. Bunnings can not supply this battery anymore. 

I found another "odd looking battery  cheap on Trademe but it seems even more odd . as I half expected it has a faulty cell. 

However on opening it up I was surprised to find it completely lacks a BMS and instead has a 50 amp ANL fuse. It is even morestrange in that it seems to fit on a Dewalt drill.  Can any one throw any light on this. I am aware of the Einhell connection so I checked a couple of now obsolete Einhell batteries but they have a BMS and yet another different  pin and slide in configuration.