Complex sentence: The 5.7 × 28mm cartridge itself is offered in a number of varieties, two of which--the SS195LF and SS197SR--are currently offered to civilian shooters for use in 5.7 × 28mm firearms.
Split into simpler sentences: The 5.7 × 28mm cartridge itself is offered in a number of varieties. The SS195LF and SS197SR varieties are currently offered to civilian shooters for use in 5.7 × 28mm firearms.