Regular expression capturing MQTT device ID

RegularEx.cs

using System;
using System.Text;
using System.Text.RegularExpressions;

class RegularEx
{
    static void Main(string[] args)
    {
        string pattern = @"(?<=^mqtt-subscription-).+(?=qos1$)"; 
        Regex regex = new Regex(pattern);
        Match match = regex.Match("mqtt-subscription-TEST-BLAqos1");
        Console.WriteLine(match);
        Console.Read();
    }
}