Brake bleed nipple size?

[Timbuick]

Need to bleed my rear brakes, can anyone tell me what tool/size is needed? It should be obvious, but the nipple is not the usual Ford/Mopar etc type that I recognise.

 

[1quick6]

Crack it loose with an 8mm deep well socket. Once loosened, I ran aquarium tubing through the socket and loosened/tightened with vise grips, shadetree mechanic style.

 

[Timbuick]

thanks, just what I needed, like the idea!