diff --git a/tests/png/hygrometer.png b/tests/png/hygrometer.png
index 57186a5..1a33edd 100644
Binary files a/tests/png/hygrometer.png and b/tests/png/hygrometer.png differ
diff --git a/vitamins/hygrometer.scad b/vitamins/hygrometer.scad
index 52a33bb..d35d3a0 100644
--- a/vitamins/hygrometer.scad
+++ b/vitamins/hygrometer.scad
@@ -29,7 +29,7 @@ flange_d = 45.5;
 flange_t = 1.5;
 flange_d2 = 32;
 flange_t2 = 2;
-apperture_d = 24.7;
+aperture_d = 24.7;
 hygrometer_hole_r = 21.3;
 slot_w = 5.5;
 
@@ -55,8 +55,8 @@ module hygrometer() { //! Draw a hygrometer
             rotate_extrude()
                 polygon([
                     [0, 0],
-                    [apperture_d / 2, 0],
-                    [apperture_d / 2, flange_t],
+                    [aperture_d / 2, 0],
+                    [aperture_d / 2, flange_t],
                     [flange_d2 / 2,   flange_t2],
                     [flange_d / 2,    flange_t],
                     [flange_d / 2,    0],
@@ -66,21 +66,21 @@ module hygrometer() { //! Draw a hygrometer
                 ]);
 
         color("#94A7AB")
-            cylinder(d = apperture_d, h = eps);
+            cylinder(d = aperture_d, h = eps);
 
         color("black")
             linear_extrude(0.2, center = true) {
                 translate([0, 3])
-                    text("20_4", font = "7 segment", valign = "bottom", halign = "center", size = apperture_d / 6);
+                    text("20_4", font = "7 segment", valign = "bottom", halign = "center", size = aperture_d / 6);
 
                 translate([7, 3])
-                    text("C", font = "7 segment", valign = "bottom", halign = "center", size = apperture_d / 8);
+                    text("C", font = "7 segment", valign = "bottom", halign = "center", size = aperture_d / 8);
 
                 translate([-1.9, 0.5])
-                    text("50", font = "7 segment", valign = "top", halign = "center", size = apperture_d / 2.7);
+                    text("50", font = "7 segment", valign = "top", halign = "center", size = aperture_d / 2.7);
 
-                translate([0, -apperture_d / 6])
-                    text("          %", font = "Arial", valign = "center", halign = "center", size = apperture_d / 6);
+                translate([0, -aperture_d / 6])
+                    text("          %", font = "Arial", valign = "center", halign = "center", size = aperture_d / 6);
             }
 
     }