They were supposed to fight in 10 oz gloves, but both camps petitioned for lighter gloves. McGregor normally wears 4 oz gloves during his MMA fights, and Mayweather normally wears 8 oz gloves during his boxing matches. The lighter gloves increase the potential of a knock out happening. See what's being said about it.
Even McGregor added a nice post about it.
I am very pleased with the Nevada State Athletic Commission's handling of my next bout today. Fair play was kept all the way through. Referee - Hall of famer Robert Byrd. Judges - Burt Clements. Dave Morreti and Guido Cavalerri. 8oz gloves approved. With pre and post fight analysis of the gloves on the night. This was handled very well and very fairly by the NSAC. I am very pleased and respect the Commissions ruling on this. 10 days until fight time.