Heatless regenerative twin tower air dry [ Heatless regenerative twin tower air dryer with final filter and auto drain valve for WAG- 7/ WAP- 4 electric locos conforming to RDSO Specn. No. MP- 0. 01. 00. 06 ( Rev. 06 ) March- 2021 to KBI drawing no. I. 3. 928 ]