Has anyone used these lifters ?

I'll be switching my cam over to solid from hydraulic on my 440/500 . If I don't start my car after a week it seems the lifters bleed down more than I ever had over the years. I know these are hydraulic . They say Anti-Pump up lifters. Is that suppose to mean they don't bleed down ? Or is it a Rhodes type lifter to help with high lift. Just curious
Anti Pump-Up Hydraulic Lifter [202HY] - $156.00 : ISKY Racing Cams, Do It Right
Opps! Forgot to add link.