This is a combination glaucoma drop. It contains brimonidine (i.e., Alphagan) and the beta-blocker timolol. This drop is usually used twice a day. Combination drops like this decrease the number of drops you have to take and tends to improve eye comfort by minimizing exposure to preservatives like BAK. This convenience may cost more, however, as both brimonidine and timolol are available as generics when bought and used separately.