Two types of tourist passes are available : one allows unlimited rides for a single day ( at HK$ 50 ) , while the other allows three days of unlimited rides on the MTR , with a stored value of HK$ 20 , refundable deposit of HK$ 50 and choice of either a single ( HK$ 220 ) or return ( HK$ 300 ) trip on the Airport Express . Cardholders may enjoy 3 days of unlimited rides on the MTR ( except Airport Express , East Rail Line First Class , Lo Wu and Lok Ma Chau stations ) refundable deposit of HK$ 50 and choice of either a single ( HK$ 220 ) or round ( HK$ 300 ) trip on the Airport Express .