If the squirter check valve is unidirectional, should I be able to blow air from one end ?
I got a new valve, can’t blow air through eith end...

The check valve should have a directional arrow molded on it, so you know the direction in which to install it.

Because it is a spring-loaded valve, you may not be able to generate enough pressure by just blowing in it. If you have a hand pump, you should be able to test it -- it should only take a few psi to open. Or, if you have a vacuum pump, attach it to the outlet and try drawing a vacuum.

Just went through this last weekend. I could not blow through it in the direction of the arrow but was able to with ~20 psi of compressed air. Thought my lungs were stronger than the are

Thanks