Safety Bump Cap with With Reflective Stripes, Lightweight and Breathable Hard Hat Head Protection Cap(Short,Black) - - Amazon.com
ERB SAFETY Bump Cap Insert: Insert Head Protection - 41N875|19402 - Grainger
Linerz Bump Cap Hat Insert Foam Head Protection Safety PPE Fits Any Hat Comfortable Lightweight Ventilated Best Bump Cap Insert (LINERZ18) - - Amazon.com
NSI Baseball Bump Cap, Custom Product Add Your Logo - 11207CP - Northern Safety Co., Inc.