I find it impossible that this person used a 2.5mm hook for weight 4 cotton yarn The circle JUST WONT CLOSE! Ive tried to up the hook and everything but the stitches are too thick! : r/crochet
Aluminium Crochet Hook 2.5MM
Metal Crochet Hook sizes 2mm to 10mm *15cm- Craft Knitting Yarn Needles Sew Tool | eBay
Amazon.com: 2.5 mm Crochet Hook, Ergonomic Handle for Arthritic Hands, Extra Long Knitting Needles for Beginners and Crocheting Yarn (2.5 mm)
Crochet Hook Sizes and Yarn Weights | KnitFreedom.com