Mark Teixeira’s Marucci MT25 Maple is cut to the CB15 profile, an MLB standard that resembles the Louisville Slugger C243. Marucci’s rep to the pros, Kyle Ourso, calls it the “traditional skinny handle.”
Teixeira’s custom model takes the CB15 and adds a bigger knob for more “butt” for the bottom hand. You can get the CB15 at the link.