-1 Run Line?

I've seen people post -1 run line bets and was wondering which books allow you to buy an extra half run.

5Dimes offers various runline options.You can play 1 run lines by betting the ml along with the -1.5 line.Example Today Phil -102 ml +189 -1.5

Bet 51-50 Ml
Bet 50-94.50 -1.5 in effect -1 Lose game -101 win by 1 -1.00 win by 2 or more +144.50