The Wilkins Type YB 1.5 inch Y Strainer with Custom Size Mesh is basically designed for very specific application. It is designed for use on a well, mounted in the specific configuration (vertically) as shown in the photo for a very good reason.
The Y-Strainer is designed to stop large (with the emphasis on large) particles being brought up from below ground by the pump. When used correctly in the proper application, there is no better and more maitenance free filter than a Y-Strainer. Most Y-Strainers come with 20 mesh as standard, and we recommend staying with that mesh.
If you want to stop finer particles, do so with a secondary filter that you can backflush out onto the ground. Otherwise, if you go with a small mesh Y-Strainer, the particles trapped will be dropping back down the pipe and slowly build up to create a problem. A smaller mesh size Y-Strainer will generally clog much quicker than a standard 20 mesh model.
When mounted in the correct configuration (vertically as shown) the particles are stopped by the screen and once the pump shuts off, the particles tend to drop back off the screen and straight back down the suction pipe. Obviously if the device is mounted horizontally, or in any position where it isn't able to self-purge itself of particles down the well, trapped particles can become a problem by clogging the screen.
If you have a problem with particles from your well, you may want to consider mounting a Y-Strainer (20 mesh) as shown to stop the larger particles, then using an easily back-flushed (onto the ground) smaller mesh filter such as the Vu-Flow type filters mounted on the discharge side of the pump to stop the smaller particles, sand, ect.