Size of nut driver for toggle pawl replacement

Tuesday night
Going on a liveaboard trip on Saturday so while putting things together....... toggle pawl breaks.
It happens to be one of the old defective ones.
Talked to Jim at ikelite (he was very helpful!!) and getting one shipped 2 day express .Arrival Thursday late.

I want to get the nut driver necessary to do the replacement prior to the parts arriving so I am ready to finish packing.

I have some small ones that you put on a screwdriver type head but they are to wide at the base and do not reach the nut (trying to remove the old one)

Any hints, ideas, wrench or nut driver size so I can head for Home Depot??

Thanks

(By the way, I still have a functional battery pack from a DS125 that works. Can it be used on the DS160...........................just in case)

We use a 1/4" nut driver to service this battery pack. You can use DS125 and DS160 battery packs interchangeably.

Regards,
Jean / Ikelite
IKELITE Underwater Systems