@Jbraswell the VSS sleeves are really excellent. As
@Hemotep pointed out, they will be having a sale this weekend.
12" fit most single LP jackets (with the exception of some single LPs that aren't actually single LP size).
12.75" will fit most smaller gatefolds. I store the records behind the record jacket so it was a tight fit for the Rhino HiFi albums but it does fit.
13" are great for Tone Poets, AS series, APs, large gatefolds, etc.
I haven't gone with their gatefold sleeves because A) I might get addicted to them and want to resleeve all my gatefolds and B) they are just way too expensive for me to justify. They are nearly $2 PER SLEEVE.