Be proactive and replace the sensing foil BEFORE you pop an old 8 track into the player.  7/32" in width (slightly under 1/4") , 3/4" to 13/16" length, cut at a 60 degree angle.  30 pre-cut tabs, comes in a protective sleeve to keep the tabs from peeling up before use. 
 
As always, I use REAL sensing foil.  Designed for audio applications.  Paper thin so that it will not get hung up at the capstan shaft.  A cheap and easy way to help avoid the tape getting eaten due to the old sensing foil splice breaking!!
 
I realize these could in theory ship out in an envelope with a stamp on it.  However I only ship items with a tracking number.  This is for your benefit and mine.  So these do have to ship First Class Package unfortunately. 
 
Shipping Details:
 
USA Customers ONLY, Shipping is a flat fee of $4.36
Orders $35 and over get FREE shipping via USPS Ground Advantage.
 
Canadian Customers, Shipping is a flat rate of 9.99 for up to $100 worth of merchandise
 
International Customers,
Shipping to most countries is $12.99 for the first $100 worth of merchandise.  This is through Asendia/USPS. 
 
Also, depending on your country, you may be charged an excise tax, VAT, etc on your end.  I do not collect any of these taxes or fees.