Based on this product's specifications, here are some alternatives and similar models
Trampoline Spring Enero for 244–427 cm trampolines, length 140 mm, brand Enero
Summary description:
Replacement trampoline spring by Enero designed for trampolines with frame diameters of 244 cm, 305 cm, 366 cm and 427 cm. Spring length 140 mm. Intended as a direct replacement part to restore bounce and tension of the jumping mat. Suitable for maintenance and repair of Enero trampolines and compatible frames with matching spring size.