Defiance spark plugs for Model T

[Papi4256]

Hello all, I have recently come across 16 Defiance model T spark plugs, but I have no idea what year they are for, or what they are worth. They appear to be new since they show no carbon or discoloration.

They have "defiance" on the ceramic and DS 35, 36, 37, etc. Does anyone know what they are, what year Model T are they for and what a fair price for them should be?

I would appreciate any help on this one.

 

[John Duden]

i have one too, would like to know more about them

 

[tmodelman]

Defiance Mfg , Toledo, Ohio made plugs for all autos and trucks up to the 1940's, when they were acquired by Autolite. Many types, pretty common in 1/2" pipe Model T size. Value about $5-$10 in good shape. Lot more if mint and still in box for Model T.
Display sign about 1938. Portion of spark plug collection for T size plugs, Defiance in the back, right.