Phillips Sonicare E Series HX5610 (Date? 140527; 5/27/14?)
These work, but are compact (small head): HX 7012 - E Series (screw on system for Essence, Xtreme, Elite, Advance)
3 Standard Heads: https://www.usa.philips.com/c-p/HX7023_64/sonicare-e-series-standard-sonic-toothbrush-heads
Walmart: $35
2 Standard Heads: https://www.usa.philips.com/c-p/HX7022_64/sonicare-e-series-standard-sonic-toothbrush-heads
Walmart $25