diff --git a/Tracking/Acts/FaserActsKalmanFilter/FaserActsKalmanFilter/LinearFit.h b/Tracking/Acts/FaserActsKalmanFilter/FaserActsKalmanFilter/LinearFit.h
index a7259dc0825bd5e471fac3b1fe129e2c6a4e8c43..f367110a4b7a05cb9bc610628995cfa6df53ddb0 100644
--- a/Tracking/Acts/FaserActsKalmanFilter/FaserActsKalmanFilter/LinearFit.h
+++ b/Tracking/Acts/FaserActsKalmanFilter/FaserActsKalmanFilter/LinearFit.h
@@ -1,11 +1,11 @@
 #ifndef FASERACTSKALMANFILTER_LINEARFIT_H
 #define FASERACTSKALMANFILTER_LINEARFIT_H
 
-#include "eigen3/Eigen/Dense"
+#include "Acts/Definitions/Algebra.hpp"
 
 namespace LinearFit {
 
-using Vector2 = Eigen::Matrix<double, 2, 1>;
+using Vector2 = Acts::Vector2;
 
 std::pair <Vector2, Vector2 > linearFit(const std::vector<Vector2> &points) {
   size_t nPoints = points.size();