Riddle: What has a head, a tail, but no body?

Riddle

i-have-keys-but-open-no-locks-i-have-space-but-no-room-a60949

Riddle

i-can-slow-you-down-or-speed-you-up-but-im-not-time

Riddle

i-speak-without-a-mouth-and-hear-without-ears-i-have-no-8fa0ce

Riddle

i-am-always-given-but-yet-always-taken-found-in-the

Riddle

i-have-keys-but-open-no-locks-i-have-spaces-but-no-room