This is a question I pose to all my fellow Level II traders out there... I used to bid/offer with hidden ISLD but was unable to get filled unless I was in front of an ISLD order. I spoke to a representative at my brokerage frim and he advised me to use RASH orders. These are essentially proactive hidden ISLD. From what I gather this is your best option if you are a scalper trader looking to get edge and your best option to get filled if your hiding your order. The weird thing is I will be bidding and offering in front of orders and I see the prints going off through my price? I thought RASH orders where supposed to have price priority? Anyways there is a bit of confusion on my part if anyone can help enlighten me a bit on this matter it would be greatly appreciated!!! Thanks and best of luck!