Head Graphene 360 + Gravity Pro MP, 315 grams, 20 mm straight beam, 6 PHL, 62 RA, medium stiff, 18x20 string pattern, 27 inches. Also available: Head Graphene 360 + Gravity Tour MP, 305 grams, 20mm straight beam, 18x20 string pattern, 4 PHL, 61 RA, medium stiff, 27 inches. Price: £200.00. Head Graphene 360 + Gravity MP, 295 grams, 20mm straight beam, 16x20 string pattern, 3 PHL, 62 RA, medium stiff, 27 inches, price: £200.00.