I can conform that U can put a custom one,
it costs about 3-4€ in ordynary watchmaker's store (see attachments pic.)
Batery life is not so good like in MBW-150. About 2 days for me.
I can't wait until someone make a plugins like Timer with vibrations on end or plugin to change vibration scheme for calls and others. TXT reader from specified folder would be nice too