how can I use noUiSlider tooltips?

[joaosalless]

how can I use noUiSlider tooltips?
I'm trying to use this way but does not work:

Session.setDefault("range_altura", [1.3, 1.9]);
    this.$("#altura").noUiSlider({
        start: Session.get("range_altura"),
        step: .01,
        connect: true,
        range: {
            'min': 1,
            'max': 2.5
        },
        tooltips: [wNumb({
            decimals: 2
        }), wNumb({
            decimals: 2
        })],
    }).on('slide', function(ev, val) {
        Session.set('range_altura', val);
    }).on('change', function(ev, val) {
        // Session.set('range_altura', [Math.round(val[0]), Math.round(val[1])]);
    });

I am very grateful if you can help me.
Thank you