Description. Head Block. Our Head Block is smaller than traditional blocks. Its the perfect size to help you achieve the correct neck alignment when in reclining positions. The Head Block is great for correcting the tilt on the pelvis (when laying down) and also great for putting between the knees to give you extra support and comfort. Buy Individually: Head Block. Sitting Block. Our Sitting Block is larger and Thicker than traditional blocks. It is the Largest Block we sell. Sitting Blocks are large Blocks which allow both your sitting bones to fit onto the block at the same time. Therefore allowing you level your posture in Yoga and Pilates postures. Ideal choice if you only want one single block (rather than 2 or more of the standard yoga blocks). Buy Individually: Sitting Block. Features. Chamfered edges to maximum comfort and grip. All Our Blocks & Bricks come Fully cellophane wrapped, to ensure they reach you in a perfect, clean condition. Size/Weight. Head Block Size: 25mm x 150mm x 205mm. Head Block Weight: 75 Grams. Sitting Block Size: 320mm x 250mm x 60mm. Sitting Block Size: 450 Grams