These are Tasbeeh(prayer beads). Muslims sometimes use them when making dhikr(remembrance of Allah{swt}). They can be made of many different materials- wood, metals(like steel or silver), pearls, ivory, glass, or precious stones. Some tasbeeh have 33 beads with two separating beads making three sections of 11, and some tasbeeh have 99 beads with two separating beads making three sections of 33 beads. One of the most common forms of dhikr is to recite "Subhan-Allah"(Glory be to God) 33 times, "Alhamdulillah"(All praise be to God) 33 times, and "Allahu Akbar"(God is the Greatest) 34 times.
The ones in the middle of the picture above are a ceramic set of 33 that belonged to my mother in law. Tariq asked me to fix them because the string had broken and the beads were loose, but they are a little heavy and no one really uses them. Each bead says "subhanAllah". The beads on the far left and the second from the right are both wooden sets with 99 beads. The second from the left(light blue) and the far right(pale yellow/greenish) are both plastic sets with 99 beads.
Some people don't use tasbeeh to make dhikr, as they see it as a bidah(innovation), so they prefer to use the joints of the fingers. My view is that if you let the tool become more important than the action(like saying-"I can't find my tasbeeh, so I can't make dhikr"), then that would be wrong, but I don't have a problem with the beads themselves.
