This is the one I use: https://flatland3d.com/shop/all-products/all-e-skate-accessories/retractable-remote-lanyard/

It's sold out and a little pricey.

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Looks like Amazon has some good alternatives.

https://www.amazon.com/T-REIGN-Retractor-Carabiner-Retraction-Flashlights/dp/B01KLYTV54/ref=sr_1_13?crid=178DIVLYWQ83E&keywords=retractable%2Blanyard&qid=1559847459&s=gateway&sprefix=retractable%2Blan%2Caps%2C186&sr=8-13&th=1