I like to get out on the bike when I'm on call & usually stick my Jabra bluetooth thingy on to take calls whilst I'm out

Anyway it decided to make a [successful] bid for freedom on a fast descent today so I need to replace it
Any thoughts on something suitable? I could do with it being quite loud but above all secure
The phone only gets used for calls so not bothered about listening to music etc.

Won't fit under my hat