Genuine Motorola Submersible Remote Speaker Microphone IP57 - Part No: PMMN4040A Compatible with Motorola Two Way Radio Models: DP3400, DP3600, DP4400, DP4400e, DP4600, DP4600e, DP4800, DP4800e The IP57 submersible RSM is tested at 1 meter for 30 minutes which is ideal for outdoor ...Genuine Motorola Submersible Remote Speaker Microphone IP57 - Part No: PMMN4040A Compatible with Motorola Two Way Radio Models: DP3400, DP3600, DP4400, DP4400e, DP4600, DP4600e, DP4800, DP4800e The IP57 submersible RSM is tested at 1 meter for 30 minutes which is ideal for outdoor radio communication in wet conditions. Intrinsic Safety Standard: UL/TIA 4950, FM The RSM incorporates both wind porting technology and waterproof capability (without Audio Jack ) Removes background noise from high winds and other outdoor noises.