performing the function of protecting the decorative light 14 and the power cords 18 are used to connect other decorative lights not shown fig6 a 6 b show the detailed construction of the light button 20 of the present invention it comprises integrally a wall portion 204 mated with the hole portion 120 used for gripping the lamp holder 16 a shoulder portion 202 projecting outward from the wall portion 204 for lapping the shell body 12 a slit 208 extending across the shoulder portion 202 and the wall portion 204 used for inserting in said power cords 18 from this slit 208 to facilitate the mounting of said decorative light 14 further more to fasten the decorative light 14 tighter the light button 20 also comprises a base portion 210 provided on the inner side of the wall portion 204 for fixing the shoulder portion of 160 of the lamp holder 16 as shown in fig4 b as the light button 20 tightly grips the lamp holder 16 the slit 208 is preferably to be made in the form of a conical slit widening gradually from the shoulder portion 202 to the wall portion 204 besides on the outer side of the wall.