FOINNEXActive Mini Displayport to HDMI Adapter 4K,FOINNEX Mini DP/Thunderbolt 2 to HDMI Converter,Supports ATI Eyefinity Multi-Screen for Gaming,Up to 6 Screens for Mac,MacBook Pro/Air,Surface Pro 3/

Having recently got a new Surface Pro I wanted to use it on a larger screen occasionally. I tried a Mini Displayport to to HDMI convertor that I got locally and I could only get 1080p out of my 1440 screen. From that failure I learnt something new, that there are two types of convertor - there's ACTIVE and PASSIVE. The original one I bought that didn't work was 'passive' and didn't support the larger resolution. THIS product was perfect, I can confirm that it really is an ACTIVE adapter, it was half the price of the official Microsoft Surface minidp adapter and worked great to output the higher resolutions that both my monitor and Surface support. Solved a really perplexing issue and taught me something new.

Using a passive HDMI cable to connect the Surface pro dock to a display adapter did not work, one forum member recommended using an active adapter. I purchased this and it solved the problem straight away and works perfectly allowing any HDMI to HDMI cable to be plugged in and used. Now I can use the two displays together when docked. Many thanks, highly recommended.

Note that it's not the correct adapter to convert a Surface Pro 6 Mini DP to a 4k60 HDMI signal. For that you'll need one like this instead https://www.amazon.co.uk/gp/product/B00S0BWR2K/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

This product work straight away with my MacBook Air 2017. Picture quality was excellent, no issues whatsoever!

I can now connect my MacBook Air to my TV. This is the only limiting feature of this model and a shame you can't cast wirelessly to a smart TV. True 4K cable at 30Hz, exactly as advertised and works a treat.