Power Crest (also known as Power Seal in the SNES/PS version) is an accessory in Chrono Trigger and Chrono Cross. Effects vary between games.
Chrono Trigger
Increasing Power and Stamina by 10 points, this accessory can be worn by any character. Power Crest is charmed from the Tera Mutant (Lower Body) and is also found within a chest in Black Omen.
Chrono Cross
Increasing Attack by 5 points, this accessory can be worn by any character. Commonly, Power Seal is stolen from Tyrano in Gaea's Navel (Home World). Rarely is it dropped by Gizmotoids in Chronopolis. To forge Power Seal, 3 Fangs and 1 Mythril are needed. This accessory sells for 1260 G.
Name Origin
Crests are components of heraldry. This crest represents a strength and so it boosts physical affinities. Official artwork of Power Crest depicts a clenched-fist, a common symbol for strength.