I use one of those, but you'll still need a hip belt to buckle in front. As the poster below linked, something like this works if you can attach it to carabiners on the side molle: https://www.amazon.com/gp/product/B00UACXYDI/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1&psc=1

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Or I use this and insert it in the battle belt: https://www.amazon.com/WANDRD-Detachable-Backpack-Waist-Straps/dp/B07JHVLWMN/ref=sr_1_2?dchild=1&keywords=ruck+waist+belt&qid=1597938258&sr=8-2