Based on this product's specifications, here are some alternatives and similar models
Tunnel element SureFlap SFA101BR
Summary description:
The SureFlap SFA101BR tunnel element is designed for pets, made from durable brown plastic. With dimensions of 380 mm in width and depth, it seamlessly connects to the SureFlap pet door, providing a secure and convenient passage for your cat or dog. Its robust construction ensures longevity, making it an essential accessory for pet owners.