A hot hemmer is so useful and this one is just genius! Made from silicone it's even firm enough to work with woo, it's heat resistant to 230°C and doesn't distort with steam. You can even use it under the edge of the fabric when ironing on fusible interfacing as the glue won't stick to the silicone. If you're using a sleeve ham, it will hug the curve on that too.

One side has a gentle curve, the other is straight. Both are marked with small holes at 0.5, 1, 2 and 3 cm to let you mark your fabric for super-accurate placement. You can also use the holes to pin through the hemmer without damaging it, and the holes let the steam through to your fabric. 

There are two corner options to help with pressing curves. For the best results on pockets, especially with thick fabrics, add a line of stitching inside the seam allowance to gather in the excess fabric evenly along the curve: you can see the result of that on the green wool.

I mean, the only way this gadget could be better is if it made the tea too!

Made in Scotland from silicone. 
Overall dimensions 190 x 70mm