Trek has updated its neoprene road shoe cover for 2008 and although it's thinner than its previous incarnation, it still does the job on those cold mornings.
Winter is, thankfully, drawing to an end in the northern hemisphere, but there never seems to be a shortage of chilly days up until about May. And there's always next winter to look forward to.
I am one of the many cyclists who suffer from cold feet. Over the years I've never managed to find a bootie that will do the job of keeping out the chill in freezing conditions. These Treks come close, and I'd even rate them as being warmer than the popular Endura overshoes, a pair of which I also own. I've ridden them in temps as cold as -1°C and as warm as 12°C, neither of which caused me too much discomfort. But in freezing conditions, I would want a bit more protection for rides lasting longer than an hour and a half.
There's nothing too complicated about these overshoes: they're made of 3mm Neoprene with a sturdy plastic base and reflective piping on the back. The zip has an auto-lock puller and doesn't dig into your ankle. There are cleat and heel holes in the base, although I found the cleat hole a little small for my Time RXS cleats. On the upside, the snug fit helps to stop too much water from leaking in via the base.
The main part of the overshoe is pure Neoprene, which provides some water resistance but isn't properly waterproof. This is fine unless you're heading out for three hours in a cold downpour. Then I'd recommend two pairs of booties - a thin waterproof set like the Castelli Pioggias and these Treks, or something similar.
The Trek booties come in one colour (black) and five sizes: S (39-40) to XX-Large (47-48). They retail for $39.99 in the US and $24.99 in the UK.