Sorry that would off helped - they are 50mm longHow long are they? There is no mug for scale ;-)
As a first guess, they are rated at 10W
Thanks for that buddyProbably not length alone. It's more like the surface area necessary to stop the component's internal temperatures rising to the point of premature failure, plus a bit for an additional margin, to allow for operation at the top end of the rated ambient temperature range, and the effects of component orientation. The 10W component, at 10 x 10 x 48mm, has a surface area of 2,120 sq.mm whilst the 20W version is 14 x 14 x 60mm, equating to a surface area of 3752 sq.mm i.e. very roughly the double the area of the 10W part. The leads will also dissipate a proportion of the heat generated during operation, and the 20W part is likely to have thicker leads.