This is the Ateco #11 standard decorating tube tip. The decorating tube tip fits with a standard coupler and it is made of stainless steel.

Specification
Ship Weight0.2 lb
ManufacturerAteco (August Thomsen)
Model Number11
Manufacturer Part #11
Type                   Piping Tips
Base MaterialStainless Steel
Color                   Silver
Shape                   Round
Tip Size                   Standard
Style                   Plain
Base Diameter SizeSmall
Tip Opening Size0.28 Inches
Hand Wash OnlyYes