BUY STOPS

BUY STOPs do not guarantee that your order will be filled.
Know how your platform or broker executes them:
Make sure that you understand the rules.

My broker sends the orders as a limit order once any trade is executed at the stipulated price.
Your broker may do buy stops differently...

Often price will jump past your level without yours getting a fill
but the order will be placed and remain open until you cancel it or it gets a fill
- or - 
there may be multiple trades at your level but your order is too far back
 in the order book and doesn't get a fill before price goes in the direction you expected.

Also be aware that some platforms will allow limit orders to be placed above the current Bid/Ask. 
These orders may be executed at current market, no matter how far above the bid/ask you placed them.
This can be problematic if you also have very tight bracket stop loss orders associated with them.