Handball
Rule

A.A.U. Four-Wall Rules · American four-wall

Rule 2

HistoricalA.A.U. Four-Wall Rules, 1923 (historical)

Historical rulebook: not the current rules. The current rules are here (USHA Four-Wall Rulebook, as of 26 January 2025).

Ball shall be standard rubber handball. (Spalding's No. 101 ball is used in the national championship tournaments.)

Mentioned here

How this rule changed

See the wording of this rule in every rulebook, with the changes marked.