Complex sentence: In 1925, Slee provided funding to Sanger's friend Herbert Simonds, who used the funds to found the first diaphragm manufacturing company in the U.S., the Holland-Rantos Company.
Split into simpler sentences: In 1925, Slee provided funding to Sanger's friend Herbert Simonds. Simonds used the funds to found the first diaphragm manufacturing company in the U.S., the Holland-Rantos Company.