Small .20 Fl Oz for small repairs. Much better than silicone for flush metal-to-metal sealing. Example: Differential Cover
Metal to Metal Anaerobic Gasket Maker
$8.50
SKU:
TUL-SMANARGM 
Product Details
This is the absolute best gasket maker when you have a clean and tight metal to metal contact. Examples of where you would use this is SEALING the rear differential cover, aluminum oil pan where is mounts to the engine block, etc.
Will not peel off like silicone or RTV and damage internal engine parts. You don't need much and the big tube is quite expensive.