Our teacher, the Buddha, taught that we should chant mantras. Why? We do not have the fortune to meet or encounter the true Buddha immediately, but we can, and do, encounter mantras. The Buddha said that after his parinirvana, he will appear in the form of letters or words. In order to recite a mantra well and experience all its benefits, one needs an appropriate mala with all the correct characteristics.
Buddhist malas have 108 beads – one hundred for counting the number of recitations, and eight extra beads to make up for the mantras that we may have recited incorrectly.
It is taught that to accomplish siddhis quickly, one should have both a private and a public mala. The private mala should be taken out only when one is doing practice by oneself, and should not be touched by others, except for your teachers when you ask them to bless the mala. The public mala can be used during prayer ceremonies (or pujas) when one is out in public.
Information Source on Malas from Akara Collection