Unthought_Known:I've used kitty litter gel beads for a couple years and they do the trick. Lifetime supply for about $10. I like to keep my humidor in the mid-60's though. If you've had your humidor at 70% in the past and you've liked it, then feel free to go for it. But if you're doing it just because you read 70% is 'perfect', then I'd recommend keeping it in the 60's. I get the best results when the humidor is a little under 70.
RaschNuts:I have the heartfelt in my 50ct. granted right now i am recharging every couple days it seems do to the NH weather. they worked great before winter hit.