| 194 / | HD | CHECK-ACTUATED CONTROL MECHANISMS |
| 302 | DF | INCLUDING MEANS TO TEST VALIDITY OF CHECK {4} |
| 328 | ![]() | .~ Having means to test surface configuration {4} |
| 329 | DF | .~.~> Raised annular rim |
| 330 | DF | .~.~> Both faces of check |
| 331 | DF | .~.~> Serrated edge |
| 332 | DF | .~.~> Apertured check {1} |