Standard invector tubes produce patterns with excellent uniform densities. It is set to industry constriction standards and are made of 17-4 stainless steel. Standard Invector choke tubes fit only Browning shotguns designed for Standard Invector and are NOT for use in shotguns showing Invector-Plus or Invector-DS on the barrel(s).
Specifications:

Type	Flush
Gauge	20 Gauge
Choke Size	Cylinder
Configuration	Invector
Finish	Stainless
Constriction	.000
Chokes Included	1
Recommended For	20 yds
Material	17-4 Stainless Steel
Approved	Steel,Lead,Non-Tox
Ported	No