They are called Keitt Mango.
We have them all over the place here in So. Florida and I have a huge one nearly 300 years old in my yard in Accompong Town.Mango Tree Keitt Variety Grafted in a 3 Gallon Container. 'Keitt' is a Florida selection which has become one of the world's most outstanding mangos. Excellent eating quality, disease resistance, productivity, and ripening time are some of the features of this four to five pound goliath. The fruit ripens from August to October. The largest fruit availble, 4-5lbs makes a great shade tree.
Just thought I would add the correction and some information.
Peace and Guidance