I made my own sea strainers. I bought stainless 316 filters and welded brackets to them. Here is why I chose to do this. One stainless clamp rated for 250psi with a thick 3/8 O ring. Virtually problem free. One wing nut and the strainer is open.
Less than 10 seconds.
Why would they put all those bolts to open?
They need to be polished but cost effective and easy to use.