This is the O Scale Surface Details Tank Car Rivets from archer fine transfers.
Sheet contains 100 linear inches (254 cm) of 3-dimensional tank car double-row resin rivets .020 inch (.51 mm) in diameter spaced vertically .064 inch (1.63 mm) and .031 inch (.79 mm) horizontally on clear decal film. Comes with instructions.
Archer Product Number: 88035
Actual sheet size is 2.75 x 4.5 inches (7 cm x 11.4 cm).