The Grom class, of which Błyskawica was one, were large, fast ships. Displacing 2,011 tons, they were about 300 tons larger than the largest pre-war British destroyer design, the Tribal class. They were designed for a top speed of 39 knots, which they managed to exceed somewhat on trials. This was faster than any British destroyer of the period, and only slightly slower than the Japanese Shimakaze, the fastest destroyer of the war. As far as armament went, their main armament was seven 4.7in (120mm) guns and two triple torpedo tubes. They had a slightly lighter gun armament than the Tribals (7 vs 8), but had an extra torpedo tube. Large American destroyers of the Porter and Somers classes had eight guns and a heavier torpedo armament, but were somewhat slower. Modern Japanese destroyers had five or six guns, but had more torpedo tubes than the Polish ships. The French and Germans built destroyers with larger guns (5.5 or 5.9in), but these ships had fewer guns than the Polish ships, with the most heavily armed ships having five guns. The Grom class are considered to be heavily armed and fast because, fundamentally, they were. However, they were also suited more for the Baltic. They were top-heavy, an acceptable risk in the calmer waters of the Baltic, but a real risk in the North Atlantic. Both ships had topweight removed after fleeing to Britain in 1939. In 1941, Błyskawica, the only surviving member of the class, was rearmed with four twin 4in mounts. This was still a respectable armament, but was considerably lighter than her original weaponry.

As far as how the Polish Navy procured such powerful ships, it's important to remember that there was a thriving export market for warships at the time of their construction. The two ships of the class were designed and produced not in Poland, but in Britain. The previous class of destroyers, the Burza class, had been designed and built by a French shipyard, the Ateliers et Chantiers de la Loire. In 1933, this shipyard was approached to design a new class of destroyers for the Polish Navy. They produced a design based on the French Navy's Le Fantasque class, produced by the same shipyard. However, the French design was rejected, and proposals sought from British shipyards. Two entered, J S White and Swan Hunter. White's design was chosen, with two ships being built in their yard. Two more were ordered from Polish yards, but were not constructed before the German invasion in 1939. Large destroyers like the Groms were fairly common in the European navies. With a heavy armament, high speeds, and large command-and-control facilities, they could lead flotillas of smaller destroyers or scout for heavier units. They were cheaper and easier to build than the light cruisers which would otherwise be carrying out such roles. For European navies whose main strategic interests were limited to the Baltic, North Sea or Mediterranean, and so did not need the range of a cruiser, these ships were attractive options.