Gardner Bender 6 AWG 3/8 in. Vinyl-Insulated Ring Terminals, Blue (4-Pack) 15-096 - The Home Depot
Amazon.com: 10pcs 6 Gauge 6 AWG x 5/16” Pure Copper Cable Lug Terminal Ring Connectors with Dual Wall Adhesive Lined Red + Black Heat Shrink Tubing – by WNI : Industrial & Scientific