This is the replacement dock ash grate for several Harman stove models but may fit others based on measurements 

Harman Magnafire Elite Insert (3) grates are required
Harman Mark II (2) grates required
Mark III (3) grates are required
*Grates are sold separately

Measurements: 21¾"L x 4"W x 3¾"H with additional dimensions shown in the image diagram