Replacing older light switch, confused about "5a 250v 10a 125v" rating
Should be fine.
You are replacing a 10A rated switch with a 15A rated switch, assuming your lights are 120V as per normal. More is better there. especially since it's unlikely that the circuit is fused or breakered at 10A.
AIUI, all 110/115/120/125V devices in the US (at least the UL-Rated ones) are actually dual-rated up to 250V, though you might have to look at the device markings rather than the packaging to see that. In any case, the 125 .vs. 120V is just a matter of nominal rating, not &quot;this will blow up if the voltage fluctuates to 121V&quot;
It may lack the 250V marking specifically because it's a &quot;lighted handle switch&quot; and thus can only operate on the one voltage, correctly. Depending on how the &quot;lighted handle feature&quot; is configured, you might get strange behaviors if the lights are LEDs rather than incandescents.