6V Golf cart Flooded Lead Acid (FLA) batteries from Costco. These have removable caps so you can add distilled water for maintenance. I only used these occasionally in the past so they don't have a lot of cycles in them. But I haven't charged them for a few years so they don't hold a charge any more. I just put them back on a charger today and they hold steady at about 6.05V to 6.07V (see picture with the volt meter). I'm selling them as is, for repair only, as they don't hold a charge any more.
Core return value is already $15 each for these batteries. Asking $20 each but I'm selling in pairs as they are designed for 12V systems, so $40 for 2 batteries. Or $75 if you buy all 4 batteries.