Note Out[26] is a list of rules (a single rule in this case), so what the Suggestion bars offers is to apply those replacement rules to an expression of our choice (to be entered in the box),
As an example, if we enter t^4 in the box and click OK, the result will be
In[27]:= t^4 /. eq3
Out[27]= {0.150354 s^4}
