Product Description Specifications Precision machined from 6AL4V titanium, this retainer features better material consistency and bullet proof durability. This 10 degree retainer fits engines with a 1.625" OD valve spring such as our 996, 998, 26099 and 991 springs. Category: Engine Components>Valve Springs, Retainers Core: N LTL: N MPN: 733-1 Proposition 65: Y Special Order: Y