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.  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!!
 
Shipping Details:
 
USA Customers ONLY, Shipping is a flat fee of $3.10  for 1 item. Orders $14 and over get FREE shipping via USPS First Class Mail.
 
Canadian Customers, Shipping is a flat rate of $14.00 via USPS First Class Small Package International Mail.
 
International Customers, I ship to most European Countries, and a few others. Shipping is via USPS First Class Small Package International and is a Flat Rate of $16.00 for up to 5 items.
 
Also, depending on your country, you may be charged an excise tax on the value of the item. This is not included in the price and out of my control.