It can protect glasses from slipping.
eBay
Sunglasses Strap for Oakley Pro M-Frame and other Sports Glasses Slash Strap Kit w/ foam strap Runner ear socks Non-Slip Hooks
Aliexpress UK
Adjustable & anti-slip Design: A rubber loop in “8” shape in the end of both side of the strap will hold your glasses arm tight. The glasses holder plays an important role for daily's use, especially sports and outdoor activities, etc.
eBay
Gold Plated Stainless Steel Glasses Chain Strap Lanyard Fashion Reading Sunglasses Eyeglasses Women Neck Hangs Mask Holder
Aliexpress UK
Adjustable Sports Sunglasses Glasses Neck Cord Strap Retainer String Lanyard UK. Great for All Sports. Not To Be Mistaken For Cheaper Quality Being Sold.
eBay
Boho Butterfly Pendant Glasses Chain Anti Slip Sunglasses Reading Glasses Lanyard Strap
Aliexpress UK
eBay
Stylish Flowers Glasses Chains for Women Fashion Colorful Mask Lanyard Sunglasses Chain Eye Glasses Holder Strap
Aliexpress UK
Protect your glasses and sunglasses while ensuring a secure fit with this stylish and functional neoprene sports band strap. Material: Neoprene (durable and stretchy). Non-Slippery: Secure your glasses and sunglasses without worrying about slippage during physical activities.
eBay
20pcs Non Slip Silicone Rubber Ring Glasses Chain Strap Eyelets Rope Sunglasses Ear Hook Eyeglasses Spectacles Loop Connector
Aliexpress UK
1PC Glasses Chain. Eva eye Glasses Case. Size:Total length 70 cm.
eBay
Newly Silicone Glasses Chain Strap Cable Holder Neck Lanyard for Reading Glasses Keeper Anti-Slip String Glasses Ropes Band
Aliexpress UK
Material: Silicone. Super soft silicone material.
eBay
5Pairs Silicone Glasses Ear Straps Comfortable Sunglasses Reading Glasses Anti-slip Holder Retainer for Sports Glasses
Aliexpress UK
Product colors: Fluorescent green, black, pink. Product material: Nylon + foam.
eBay
Eyeglasses String Holder Strap - Eyeglass Holder Chains for Women Man - Glasses Chain Lanyard Cords - Neck Sunglass Strap
Aliexpress UK