External monitor for 13' MBP 2015 recommendation?

[cerberusd]

Hello, I have a 13 inch retina mbp that I bought earlier this year, and I'm looking to buy a monitor that has the same or better resolution as the mbp's screen. Am I looking at 4k? And if so, what would be some of the monitors that the 2015 13 inch mbp can support?

 

[junkw]

highest pixel density for 3840 x 2160 is the Dell p2415q

 

[july142]

lg 34 inch ultra wide