like a hard case sleeve? This is what I use on my 13T with some wiggle room:

​

The 11-12.3" version fits the 13" Spectre perfectly fine:

https://www.amazon.com/gp/product/B07GP3LG3K/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

​

Silicon Keyboard cover:

https://www.amazon.com/gp/product/B07CYRGPND/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1