The pin strips at the edge of the carpet.
They are called pinless tack strips, painless tack, my worst nightmare and by their trademarked name which is the original pinless tackstrip... Smooth Edge.
Fun fact, John Robert's held the first patent (that I know of) for "smooth edge". The irony in the name is that its spikey death to all installers but it eliminated the requirement for carpet tacks on wall to wall installations. Those tacks would make the carpet appear puckered or "lumpy" where they were placed. Hence the name
They are called pinless tack strips, painless tack, my worst nightmare and by their trademarked name which is the original pinless tackstrip... Smooth Edge.
Fun fact, John Robert's held the first patent (that I know of) for "smooth edge". The irony in the name is that its spikey death to all installers but it eliminated the requirement for carpet tacks on wall to wall installations. Those tacks would make the carpet appear puckered or "lumpy" where they were placed. Hence the name