The 5.5kg (12lb) density of these recycled chip foam yoga blocks makes them the firmest chip foam block available. (cheaper foam blocks lack the density and durability of these). Blocks enhance your practice by supporting, stabilising and aligning the body. Sit on one to raise your hips for a straighter spine, or put four together for a classic shoulder stand support.Our Chip Foam Blocks are made in England U.K. We always source locally if possible.Please note - these blocks are not as dense as our EVA foam blocks and in comparison have a softer/squishier feel to them. If you're looking for a firm block we recommend our EVA half blocks. Blocks are usually used in pairs but please note these are sold singularly. Size -Length: 20cm (12" Inches)Height: 2.5cm (1" Inch)Width: 15cm (6" Inches)Product details: Help to aid alignment in yoga poses Softer support than EVA foam blocks Made from recycled chip foam