In early May 2013, we happen to come across the amber necklace in Berlin at a Weimeraner bitch - who can recognize crude Bernstein if he had not violent Baltic contacts. From Kehuna.at delivery came immediately (from Nuremberg camp), since 14 days carrying our 2 1/2 year old longhaired PON bitch this - and still has not a single tick, neither in Berlin Grunewald still in the woods and fields in Upper Franconia. Other friendly dogs already. So the static electricity and the essential oils (Bernstein's very old resin) seem to work. We're doing a field test with 3 dogs, been very successful. The necklaces are also resilient, so far brawls and Undergrowth Durchstreifungen have defied the dogs it goes well, they notice the strings barely. Anyway, we are thrilled to finally no more expensive chemicals.