I have an outside breaher box manufactured by walker electrical company model number P147794 I don't know what fuse I need as the old ones are missing
Sam

You said you have a breaker box but you say you are missing a fuse. Breaker boxes have breakers not fuses. Do you mean you have an exterior fused disconnect box. If so what kind of fuse? The buss type that are held in clamps or the screw in type? Either type should be generic. The size would depend on the load and the wiring going out of the disconnect box. So what type of box is this and what does it feed?

I don't know what I'm missing maybe some sort of a pull out there are two rectangular boxes at top of panel each one has two slots at the sides wish I could show a picturs
Sam

I have seen fuse panels with switches next to each screw in fuse for 120 volt circuits and pullout fuse holders hloding two fuses for 240 volt circuits.

I have never heard of a Walker Electric that makes fuse or breaker panels, and unable to find any reference on the internet, but fuses are made in standard sizes to go into any manufacturers equipment.

The Walker I know makes floor boxes.

Bring the fuse holder to a electrical supply to match up the physical size of the fuse. You will need to know what amperage fuse is required for the circuit size.

Re-reading your question, seems the pullout fuse holder is missing. In that case, finding a replacement may be a problem.

You may need to replace the panel.