It is, but I'm not sure if the holder will fit the camera. I found a supplier who is checking to see if the external battery holder for the Mamiya 7II will fit and am still awaiting his reply.
Many thanks
Steve.
PS: I have already managed to buy a second hand Macro tube on eBay.
I use the same tweezers that stamp collectors use. It has flat paddle like tip instead of the usual pointed tip. You should be able to buy it at your local hobby shop.