Outside, professional, testing shows an increase of 10-15% in bat speed when using ThumbPRO.
Features:
Ergonomically engineered to fit your hand and stay in place swing after swing
Enables proper bat grip, unlocking your optimal swing by getting the bat up in your fingers and avoiding the "death grip" that can hold you back
Prevents bat sting without the fear of getting jammed
Sizing:
It is suggested using a string or ribbon to measure around the circumference of the thumb, halfway between the base and the first knuckle of the thumb.
Measure in a way it will be used at-bat. If the player wears a glove, measure with the glove on.
Large -- 2-3/4" circumference (generally above 205 lbs.)
Medium -- 2-1/2" circumference (generally 130-205 lbs.)
Small -- 2 1/4" circumference (good for Youth and Adults under 130 lbs)
This is a general recommendation. Some like a looser fit and others prefer a snug performance fit.
At Closeout Bats we stock what we sell! We have a huge warehouse and are NOT drop shipping bats like many web sites. We update inventory and availability on the Web site several times a day as inventory positions change shipping hundreds and hundeds of bats. We also sell bats out of our physical store, so sometimes things sell out before we can get them off the Web site.
Limited quantities available. Prices subject to change without notice. Like we say, if it's on the site, it's in the warehouse -- just SOMETIMES it might have some other player's name on it! If you snooze, you lose, so ORDER YOURS NOW!
ThumbPro White Lightning Thumb Guard 
