The center label says:

The words, "MADE BY" are replaced with a dash-dot-dash and "Co" is added after "SON."

"TRADE MARK" is replaced by, "TRADE MARK REG. U. S. PAT. OFF."

"J.F.HILLERICH & SON Co" is changed to, "HILLERICH & BRADSBY Co."

The dash-dot-dash under "LOUISVILLE SLUGGER" is replaced with "125."

The number 125 denotes a professional model bat to this day.

The dash-dot-dash under "HILLERICH & BRADSBY Co" is replaced with, "MADE IN U.S.A."

"Powerized" appears right of the center label. Underneath "Powerized" is "Pat. Pending."

"Pat. Pending" is replaced with the phrase, "Bone Rubbed."

Also, the word "GENUINE" first appears on the barrel above the player's name.

"Bone Rubbed" is replaced with the phrase, "Oil Tempered."

"Powerized" appears alone for the first time.

If a bat has the 1921-31 center label and "Powerized" by itself, it must be from this era.

"TRADE MARK REG. U. S. PAT. OFF." is replaced under the center label with the words, "TRADE MARK REG."

The word "Powerized" has several different looks during this period (and through 1949). Generally, it will look more condensed than the version that begins in 1950 and the lightning bolts will be more pronounced or jagged.

Model numbers are stamped into the knob of the bat beginning in 1943. By the end of 1944, all bats produced have the model number stamped into the knob.

The model numbers are the only trait that differentiate this era from the 1934-44 era.