Made from 1/2 thick solid steel Other thickness available is 5/8 and 3/4 Available in zero clearance, standard, medium and heavy-duty grades ranging in sizes from 18 to 36. Each grate is also available with Ember retainer. The Ember Retainer Grate has a built in channel for holding our Fire Starter product or kindling. Ember Reatiners will hold the embers of your fire for a hotter, more efficient fire. 1/2" Square Bar Steel Grate options 18' Grates are avalable with 4 or 5 bars 23" Grates are available with 5 or 6 bars 27" Grates are available with 5 or 6 bars 30" Grates are available only with 6 bars 5/8" Square Bar Steel GRate Options 18' Grates are avalable with 4 or 5 bars 23" Grates are available with 5 or 6 bars 27" Grates are available with 6 bars 30" Grates are available only with 6,7 or 8 bars 3/4" Square Bar Steel Grate Options 23" Grates are available with 5 or 6 bars 27" Grates are available with 5 or 6 bars 30" Grates are available only with 7,8,or 9 bars.