Quote from Shanb:
maybe this SHY-TLT might work a bit better. Looks pretty close
SHY-IEF would be the closest in duration. TLT would work better with IEF as in IEF-TLT.
The 2/10 and 10/30 are really popular trades with the 2/10 probably being a little more popular.
STPP is going to be MUCH more marginal friendly for retail guys. If you are going to hold this for 6 to 12 months the liquidity won't matter much. This is really a long term trade.