Sorry, I meant one is 500gb, and the other is 1T. The specs when you compare them both, the 2 SER5s, are close. The SER6 Pro I saw on sale was this one:

https://www.amazon.com/dp/B0BBMRV5TN?ref_=cm_sw_r_mwn_dp_GHX66N3PW71Y1HHXW2XD