Most sources agree on 7.5% heal & 9s cooldown. One older guide lists 7.5s; current consensus uses 9s. Item rarity is not consistently published by official channels; marked as Unknown.
Each time you hit an enemy, Slurp Gloves can cast a short blood magic pulse that damages nearby enemies and heals you for 7.5%. This on-hit effect has a 9-second cooldown, so it’s a steady sustain tool rather than a burst heal.