Waterproof Phone Pouch 2-Pack, Double Space Waterproof Phone Case For IPhone 15 16 17 Pro Max Up To 7", Cellphone Dry Bag With Lanyard For Beach Kayak Cruise ,Travel Essentials- Cell Phone Waterproof Bags free Returns Free Shipping. 

it fits a smartphone up to 7 inches

the holder min length (16.9 in\43 cm) and Max length (33 in\84 cm)