Up for sale here is this lot of 5 NOS vintage ElMenco 250 pf 500v 3% silver mica capacitors.  They will test very close to their marked rating. These are high-quality silver mica caps, and will work great for you. Please see my pictures for details.

US shipping and handling is $5, and international is $18, no matter what quantity you buy. All of my small parts are set up for combined shipping--just use the "add to cart" feature and then check out at once, and the shipping will be automatically discounted. If you have any questions, please ask.

I have more capacitors and other vintage electronics listed--feel free to take a look!