For weight, the match will be contested at 154 pounds. That's an advantage for McGregor, who has fought as high as 170 pounds in the past and is the current UFC 155-pound champion. Mayweather, meanwhile, has competed at weights as low as 130 pounds, with his later bouts sitting around 145 (although he did agree to 152 pounds for his fight against Saul "Canelo" Alvarez). In the past Mayweather has forced larger fighters to compete at lower weights, but in this case McGregor will get to carry his typical UFC weight into the ring, giving him a decent size advantage over Mayweather.
The glove size for the bout has been set at 10 ounces. Compare that to MMA gloves, which are between 4 oz. and 6 oz. and boxing gloves which range from 8 oz. to 20 oz. Mayweather has worn 10 oz. gloves for many of his recent fights, and this goes along with Nevada statute that sets 8 oz. gloves for fights under 147 pounds and 10 oz. gloves for those above.