WELDED INSIDE AS WELL AS OUT SIDE,, COMES WITH NO PUSH AND TWIST CAP, JUST USE STANDARD CAP OFF YOUR CAR WILL FIT FINE.. HAND MADE TO ORDER and posted OUT IN 1 DAY THATS FAST LET ME KNOW ON ORDERING WHAT TYPE YOU NEED, THERE ARE 3TYPES OF TANKS ITS EASY,, MEASURE THE X 2 HOLE CENTRES IN THE MOUNTING BRACKET ON YOUR TANK BUT PLEASE IF POSSIBLE SEND ME A CLOSE UP PIC OF YOUR TANK ITS ALOT BETTER ON ORDERING SEND ME A PIC though eBay, MUCH EASIER GAINS OF BUYING THIS ITEM..NEVER LEAKS LOL. ♦ Check out the latest chromed and polish aluminium engine products from BADASS PERFORMANCE. ♦ We deal with many makes of cars and can make any one of covers, induction kits, pipe work, intercoolers, radiators, and more. ♦ You can also book your car in for a day or two and have the hole engine chrom