Suited connectors are defined primarily as speculative hands. These starting hands should always be a certain way to improve on the flop, so that they can continue the game was. In most cases, while, on the flop we get into the draw is often strong enough to draw. Strong suited connectors start at 54s. This hand has the capability to hit once in two possible draw. On the one hand, it is, of course, a flush draw, on the other hand, a straight draw. At the same time, in order to have the best chance of getting into the straight, connectors should be able to build a straight due to three consecutive cards from either side, both above and below. So for the lower 54s will be supplemented by a straight cards A23. Given this setting, it can be said that the most "strong" speculative hand is considered JTs. With the same hand as QJs, we no longer have the maximum chance of a straight draw, but it gets a certain additional equity due to the seniority of the cards and thus have more chance of getting into a pair of strong, although it should not be forgotten and the possible domination. Therefore QJs classified slightly weaker than JTs. At the same time, such a hand as 43s, will be a considerably weaker.
Since we do not want to play hands that are at risk of being under domination, then, first of all, as a playable suited connectors we consider the range of hands 54s-JTs.