[Solved]-Highcharts - How can I show arrow between two dials of gauge chart?-Highcharts

You can add thickness and use linearGradient as

https://jsfiddle.net/viethien/s90gk1tc/15/

{
         thickness: 1,
           from: 60,
           to: 78,
           color: {
                    linearGradient: [300, 300, 0, 0],
                    stops: [
                        [0, '#55BF3B'],
                        [1, '#FFF']
                    ]
                } ,
           /* innerRadius: '100%', */
           outerRadius: '50%',
   }