I know that you've already ordered but.... I agree with vol's post above ^^^^ I've been using 'Nite Ize SpokeLit' spoke lights (http://bit.ly/TN13iS) for about a year now and haven't had any problems. You can find them at any LBS and on Ebay/Amazon as well.... They take (2) 3V CR2016 batteries which you can purchase inexpensively by the card on Ebay or Amazon. You can easily install and remove them and they grip really well. I don't really ride in rain.. (I live in So Cal..where it rarely rains).. so I don't know about a good waterproof test. I run mine on strobe for the most part so that it conserves battery life. Along with my Cygolite front and rear lights, Cars and pedestrians see me...... I've seen the combo literally stop people in their tracks. (which in my opinion is needed)