Your search for "sr300*" revealed the following:
ZOTEE 300 sq.ft. Filtration Cartridge Pool Filters System - Inner and Outer Set
Specifications Inner Cartridge: 8-3/4" * 25-1/4" Outer Cartridge: 16-1/2" * 18-3/4" Sold as a set for the S7M120 300 sq.ft. filter Max...
$399.99
$259.99