Primal Gladiator's Satin Treads is part of the transmog set Primal Gladiator's Satin Armor (Priest only), which the Appearances collection lists in 2 versions. The other 13 pieces:
Items Numbered Next to Primal Gladiator's Satin Treads
Blizzard numbers items as they are created, so the named items next to ID 115968 (115963 to 115973) were usually added in the same batch as Primal Gladiator's Satin Treads: the same quest line, zone, vendor or reward set.