You can make one by using one of those heat shrinking tubes, when heated it it will take the shape of the grooves also.
https://www.amazon.com/Shrink-Tubing-GLE2016-Black-Adhesive-Lined/dp/B01MD1Z124/ref=sr_1_3?dchild=1&keywords=shrinking+black+tubes&qid=1610522275&sr=8-3