Hoping for some advice on buying a TENS. I'm now 30 weeks and expecting baby number 1 - and in an ideal world plan on having a few more; so buying a tens machine makes more sense than hiring one. There seem to be so many different brands on the market and at such a wide range of prices. I want to invest in a model that will be useful up to 5cm dil and want to avoid buying a machine that offers very limited pain relief. What are your experiences with the models you have hired and purchased? Thanks!