Want ITB sock filters but dont want to pay heaps for them? I have designed a trumpet to fit the filters beloe.

https://www.aliexpress.com/item/1005006121587631.html?spm=a2g0o.cart.0.0.218238da5zvBvR&mp=1&pdp_npi=6%40dis%21NZD%21NZD%2024.51%21NZD%208.15%21%21NZD%208.15%21%21%21%40210318a717697564753761010e36cf%2112000035849097539%21ct%21NZ%213106905092%21%214%210%21

They are reinforced and designed for the filter to screw straight on.