The BLK BOX Strongman Sandbags are refillable heavy-duty vinyl sandbags for strongman, functional strength and conditioning training, offered for fill weights from 20 kg to 100 kg in 10 kg steps. They are double stitched, with an inner stitched filler bag and a double-stitched zip to stop sand escaping during use. They are supplied empty, should be filled with sand only, and are designed to be dropped, not slammed. KEY SPECIFICATIONS Brand: BLK BOX Product type: Strongman sandbag (refillable) Weights and SKUs: 20 kg 16-0401; 30 kg 16-0402; 40 kg 16-0403; 50 kg 16-0404; 60 kg 16-0405; 70 kg 16-0406; 80 kg 16-0407; 90 kg 16-0408; 100 kg 16-0409 Listed sizes: 20 kg 120 x 400 mm; 30 kg 170 x 400 mm; 40 kg 220 x 400 mm; 50 kg 270 x 400 mm; 60 kg 320 x 400 mm; 70 kg 380 x 400 mm; 80 kg 430 x 400 mm; 90 kg 480 x 400 mm; 100 kg 540 x 400 mm Material: double-stitched heavy-duty vinyl fabric Closure: inner stitched filler bag with velcro fastening; double-stitched zip Fill: sand only (kiln dry sand recommended); do not use pebbles, gravel or other aggregate; filler not included Use: designed to be dropped, not slammed USE AND TRAINING Exercises: overhead press, ground to shoulders, floor pre