Bosch LBC 3437/00 and LBC 3438/00 horn speakers are specially designed and certified for installation in environments where explosive gas mixtures may exist. They can be used in any mixture of gases, including hydrogen. The rated power of LBC 3437/00 is 15w, and LBC 3438/00 is 25w. The basic functions of the two loudspeakers are made of uv-resistant glass reinforced polyester (GRP). This strong fire-resistant material provides greater reliability and reduces maintenance costs. In addition, GRP has excellent chemical resistance and thermal stability, making it easy to cope with various applications, including the worst environment. The two speakers are all-weather, stainless steel mounting bracket and retaining cover screws, as well as stainless steel welding, further improving corrosion resistance. Standard equipped with an EExdIIC seal plug. All Bosch speakers are certified to meet IEC 268-5 power handling capacity (PHC) standards and can operate continuously for 100 hours at rated power. Bosch has also conducted simulated acoustic feedback exposure tests to ensure they can withstand twice the rated power in a short period of time. This ensures high reliability of the speaker under extreme conditions, improves customer satisfaction, extends service life, and significantly reduces the probability of failure or performance degradation. Flame retardant compliance UL 94 V1 class waterproof and dust proof compliance EN 60529, IP 66 and IP 67 ATEX Ex Ex II 2 GD BASEEFA * EExd II C T5, area 1 and 2 (LBC 3437/00) EExd II C T4, Zone 1 and 2 (LBC 3438/00) certification number BAS00ATEX2097X CENELEC 50014 EN 50018 * * * EN BASEEFA = for flammable environment of electronic equipment in the certification service organisation * * CENELEC = electronic standardization organization of Europe certification European CE BASEEF installation/configuration horn speaker built-in transformer, A jumper wire on the primary winding can be used in different