About products and suppliers:
Alibaba.com offers 3933 horn coil products. About 21% % of these are speakers, 9%% are speaker & horn. 

A wide variety of horn coil  options are available to you,  such as aluminum, iron and abs.You can also choose from 2-way, tweeter and coaxial horn coil,As well as from 12v, 24v horn coil. and whether horn coil is universal, toyota, or honda.