Gravity's special offer 6 HIIT Fitness Class Pass is just £24! That's 6 uses at only £4 per session saving £6. Buy online now and bring the voucher with you next time you visit and we'll assign your pass to your account - a photo will be taken for identification verification. Pass is valid until 31 Dec, is non-refundable, non-transferable and only valid for the park purchased for. Book HIIT Fitness sessions in park or by phone only