According to one aspect, transaction information is received and applied to multiple fraud risk mathematical models that each produce a respective raw score, which are transformed with respective sigmoidal transform functions to produce optimized likelihood of fraud risk estimates to provide to a merchant. The cooling section includes a plurality of flow tubes, each flow tube having an inlet, an outlet, and a bounding wall that defines a closed fluid flow path from the inlet to the outlet. The communicator monitors each of two or more wireless carriers for a service characteristic. The hash value is calculated at the user’s computer, and then submitted as a designated password to a server. Each channel and its respective end of the handle have matching locking teeth that form an interlocking mechanism with the locking teeth in the channel in locking engagement with the locking teeth on the handle end.