Cortina 03-730 Square Base, 10lb, 15" Length, 14" Width, 3" Height

Works as intended for that of course, but also good for holding down temporary poles (mounted on a wood base which this slips over) for parties or garden or such. We used these to hold down (against the wind) an flat wood-based ABS pipe umbrella stand for a large gardening rain/sun shade umbrella that my wife uses when sitting down doing volunteer public garden weeding.Note - if you need to cut the hole larger, a sabre saw would be easiest - but a coarse-tooth hand gardening limbing saw or strong drywall saw works also to cut the VERY tough rubber, which I guess is made of fused pieces of scrap tires. Knives, other hand saws, sawzall - not so much.Looks like it will last pretty much forever.