Weaving Temples make keeping straight edges on your weaving easier. These temples are made in smoothly finished wood so they don’t scratch your loom or prick your fingers. It's just one of those tools that when you need one, you need one. The teeth in temples are made thin for easy gripping of material (without punching holes in your projects) and extremely sharp. While temples are typically not necessary when weaving tea towels or quick wool scarves, they are extremely helpful in making rugs and table linens, where straight edges are desired.
Weaving Temples are made to work within a range of widths, the longer ones with a wider range. They are also thicker and wider. Weavers generally have more than one temple, selecting the sizes which work with the weaving widths they use most often. To find the correct width for your temple, place the it upside down against the reed and choose the pinhole that is closest in size as your sleyed warp. It's better to have the temple width a bit smaller than too big, ideally the pins or tenterhooks should just sit at the edge of the woven cloth. First adjust the temple's size so that it does its’ job of maintaining the warp width as sleyed in the reed and prevents narrowing of the woven cloth as you weave the web. While it may seem like this will create more work and hinder your rhythm, the benefits truly outweigh any inconveniences in shifting them. It's a matter of just getting used to it.
I carry most sizes in stock at all times, as listed here: