These are quite good when doubled up with foam plugs. I use them at indoor ranges to great effect.
Howard Leight by Honeywell Impact Pro High Noise Reduction Rating Sound Amplification Electronic Shooting Earmuff for Indoor and Covered Ranges or Other Extremely Loud Shooting Environments (R-01902) https://smile.amazon.com/dp/B007BGSI5U/ref=cm_sw_r_cp_api_glc_fabc_l8IZFbBZCT1TM
Howard Leight by Honeywell Impact Pro High Noise Reduction Rating Sound Amplification Electronic Shooting Earmuff for Indoor and Covered Ranges or Other Extremely Loud Shooting Environments (R-01902) https://smile.amazon.com/dp/B007BGSI5U/ref=cm_sw_r_cp_api_glc_fabc_l8IZFbBZCT1TM