A beater or batten, is a weaving tool designed to push the weft yarn securely into place.
Beaters appear both in a hand-held form, and as an integral part of a loom.
[1] Hand beaters must have enough mass to force the weaving into place, so they come in a variety of weights and sizes.
Some may have lead inserts to provide additional heft for a smaller beater, and some are made entirely from metal.
The actual beating is done by a metal insert known as a reed, which contains a number of slots, known as dents, which the warp threads pass through.