This set comes with the Grover 1601 Dual connected Truktone air horn and 1734 installation kit for vehicles equipped with air brakes
Authentic Grover Products Co. #1650 Air Horn 
Dual Connected Truktone™ Air Horn
15 ¼” long bell, 13 ¼” short bell; 4” flares
chrome finish with #1734 kit! 
pedestals sold separately: 1819
weather shield pair sold separately: 1652
Volvo Part 8889203, Replaces Volvo: G15508493, G2076015, V1591866, V8889203, 02-7074793, 63001-0010
Don’t fall for cheap replicas/knock-off horns. 
Always check for the Grover Products Co. Logo on the back of your horns!