What heatable eye mask would you recommend?

I bought a gel eye mask a while ago, which I heat in the microwave.  However, the heat is not very well dispersed throughout the mask and I'm wondering about buying a different one.  Can anyone recommend an eye mask that works for you?  Also, for how long do you leave the eye mask on?

I prefer either a heated or a chilled wet wash cloth. 😀 Dena

Thera pearl eye mask is the only one worth using. you do warm it in microwave but it totally holds its heat. 

I agree with Andy, having tried three different eye masks plus heated wet towel, the therapearl microwavable eye mask the best. I do find that I need to use it for a minimum of 7/8 minutes however. The recommended five minutes I find too short.n Mine is about three months old and I have used it twice a day for most of that time, it still works fine. Fortunately I'm now moving to once a day and things seem to be holding up

Thank you all for your suggestions.  Extremely helpful.