N A recent paper, Bertola and Cafaro [1] posed a design problem for cooling fins whereby the temperature boundary condition at bothends(Tb atthebaseand Tt atthetip)andtheheat fluxatthebase qb were specified, and it was desired to determine the corresponding fin length L. Their analysis appeared to assume a free-ended tip, as indicatedbyFig.1intheirpaper,andtherateofheattransferatthetip was not considered. Their mathematical analysis based on onedimensional, steady-state heat conduction led them to conclude that for fixedvaluesof Tb and Tt,thereisarangeof qb forwhichthereare two possible solutions for L. Bertola and Cafaro attributed the existenceoftwopossible solutionstotheuseofthreeconditions(Tb, Tt, and qb) in solving the pertaining second-order differential equation. It is demonstrated in this Comment that the two solutions, while mathematically possible, correspond to two completely different physical arrangements and thus, they cannot be considered in design as alternative solutions to the same set of conditions. It is also shown that fins with prescribed tip temperature are typically connected to another body at the tip, except for a certain restrictive condition. Consider a fin of uniform cross-sectional area Ac, perimeter P, length L, thermal conductivity k, base temperature Tb, and tip temperature Tt immersed in a medium at a temperature Ta with a uniform convection heat transfer coefficient h (as shown in Fig. 1). The governing energy-balance equation is given by [2–4]